diff --git a/CHANGELOG.md b/CHANGELOG.md
index 514599e57..41695f0a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ Changes:
 
 - Add `arrayZip` to combine a key + value array into entries-like
 - Assert `chainCode` inputs to `derive*`, protecting against misuse
+- Adjust base library usage of `for` vs `reduce/map`
 - Adjust testnet detection in `@polkadot/networks`
 - Bump Ledger libraries to latest versions
 
diff --git a/packages/keyring/src/keyring.ts b/packages/keyring/src/keyring.ts
index bfbcee41a..ab0dfb2c4 100644
--- a/packages/keyring/src/keyring.ts
+++ b/packages/keyring/src/keyring.ts
@@ -262,11 +262,7 @@ export class Keyring implements KeyringInstance {
    * @description Returns an array list of all the public keys associated with each of the keyring pair values that are stored in the keyring pair dictionary.
    */
   public getPublicKeys (): Uint8Array[] {
-    return this.#pairs
-      .all()
-      .map(({ publicKey }): Uint8Array =>
-        publicKey
-      );
+    return this.#pairs.all().map(({ publicKey }) => publicKey);
   }
 
   /**
diff --git a/packages/keyring/src/testing.ts b/packages/keyring/src/testing.ts
index 1f92b6343..7c08fc9bf 100644
--- a/packages/keyring/src/testing.ts
+++ b/packages/keyring/src/testing.ts
@@ -121,7 +121,7 @@ export function createTestKeyring (options: KeyringOptions = {}, isDerived = tru
   const keyring = new Keyring(options);
   const pairs: PairDef[] = (options.type && options.type === 'ethereum') ? PAIRSETHEREUM : PAIRSSR25519;
 
-  pairs.forEach(({ name, publicKey, secretKey, seed, type }): void => {
+  for (const { name, publicKey, secretKey, seed, type } of pairs) {
     if (!name && !seed) {
       throw new Error('Testing pair should have either a name or a seed');
     }
@@ -139,7 +139,7 @@ export function createTestKeyring (options: KeyringOptions = {}, isDerived = tru
     pair.lock = (): void => {
       // we don't have lock/unlock functionality here
     };
-  });
+  }
 
   return keyring;
 }
diff --git a/packages/keyring/src/testingPairs.ts b/packages/keyring/src/testingPairs.ts
index bf1b46433..39d942131 100644
--- a/packages/keyring/src/testingPairs.ts
+++ b/packages/keyring/src/testingPairs.ts
@@ -15,11 +15,9 @@ export function createTestPairs (options?: KeyringOptions, isDerived = true): Te
   const pairs = keyring.getPairs();
   const map: TestKeyringMap = { nobody: nobody() };
 
-  return pairs.reduce((result, pair): TestKeyringMap => {
-    const { name } = pair.meta;
+  for (const p of pairs) {
+    map[p.meta.name as string] = p;
+  }
 
-    result[name as string] = pair;
-
-    return result;
-  }, map);
+  return map;
 }
diff --git a/packages/util-crypto/src/address/derive.ts b/packages/util-crypto/src/address/derive.ts
index ee4fe27ee..7d0dbb510 100644
--- a/packages/util-crypto/src/address/derive.ts
+++ b/packages/util-crypto/src/address/derive.ts
@@ -7,7 +7,6 @@ import type { Prefix } from './types';
 import { assert } from '@polkadot/util';
 
 import { keyExtractPath } from '../key';
-import { DeriveJunction } from '../key/DeriveJunction';
 import { schnorrkelDerivePublic } from '../schnorrkel';
 import { decodeAddress } from './decode';
 import { encodeAddress } from './encode';
@@ -21,9 +20,13 @@ import { encodeAddress } from './encode';
 export function deriveAddress (who: HexString | Uint8Array | string, suri: string, ss58Format?: Prefix): string {
   const { path } = keyExtractPath(suri);
 
-  assert(path.length && !path.some((path) => path.isHard), 'Expected suri to contain a combination of non-hard paths');
+  assert(path.length && !path.some((p) => p.isHard), 'Expected suri to contain a combination of non-hard paths');
 
-  return encodeAddress(path.reduce((publicKey: Uint8Array, path: DeriveJunction): Uint8Array => {
-    return schnorrkelDerivePublic(publicKey, path.chainCode);
-  }, decodeAddress(who)), ss58Format);
+  let publicKey = decodeAddress(who);
+
+  for (const { chainCode } of path) {
+    publicKey = schnorrkelDerivePublic(publicKey, chainCode);
+  }
+
+  return encodeAddress(publicKey, ss58Format);
 }
diff --git a/packages/util-crypto/src/hd/ethereum/index.ts b/packages/util-crypto/src/hd/ethereum/index.ts
index f395d808c..b21a96669 100644
--- a/packages/util-crypto/src/hd/ethereum/index.ts
+++ b/packages/util-crypto/src/hd/ethereum/index.ts
@@ -44,7 +44,7 @@ function deriveChild (hd: CodedKeypair, index: number): CodedKeypair {
 
 export function hdEthereum (seed: Uint8Array, path = ''): Keypair {
   const I = hmacSha512(MASTER_SECRET, seed);
-  const hd = createCoded(I.slice(0, 32), I.slice(32));
+  let hd = createCoded(I.slice(0, 32), I.slice(32));
 
   if (!path || path === 'm' || path === 'M' || path === "m'" || path === "M'") {
     return hd;
@@ -52,16 +52,15 @@ export function hdEthereum (seed: Uint8Array, path = ''): Keypair {
 
   assert(hdValidatePath(path), 'Invalid derivation path');
 
-  return path
-    .split('/')
-    .slice(1)
-    .reduce((hd: CodedKeypair, c): CodedKeypair =>
-      deriveChild(
-        hd, parseInt(c, 10) + (
-          (c.length > 1) && c.endsWith("'")
-            ? HARDENED
-            : 0
-        )
-      ), hd
-    );
+  const parts = path.split('/').slice(1);
+
+  for (const p of parts) {
+    hd = deriveChild(hd, parseInt(p, 10) + (
+      (p.length > 1) && p.endsWith("'")
+        ? HARDENED
+        : 0
+    ));
+  }
+
+  return hd;
 }
diff --git a/packages/util-crypto/src/hd/ledger/index.ts b/packages/util-crypto/src/hd/ledger/index.ts
index 1f859220e..fa0e8869e 100644
--- a/packages/util-crypto/src/hd/ledger/index.ts
+++ b/packages/util-crypto/src/hd/ledger/index.ts
@@ -12,27 +12,28 @@ import { ledgerDerivePrivate } from './derivePrivate';
 import { ledgerMaster } from './master';
 
 export function hdLedger (_mnemonic: string, path: string): Keypair {
-  const parts = _mnemonic
+  const words = _mnemonic
     .split(' ')
     .map((s) => s.trim())
     .filter((s) => s);
 
-  assert([12, 24, 25].includes(parts.length), 'Expected a mnemonic with 24 words (or 25 including a password)');
+  assert([12, 24, 25].includes(words.length), 'Expected a mnemonic with 24 words (or 25 including a password)');
 
-  const [mnemonic, password] = parts.length === 25
-    ? [parts.slice(0, 24).join(' '), parts[24]]
-    : [parts.join(' '), ''];
+  const [mnemonic, password] = words.length === 25
+    ? [words.slice(0, 24).join(' '), words[24]]
+    : [words.join(' '), ''];
 
   assert(mnemonicValidate(mnemonic), 'Invalid mnemonic passed to ledger derivation');
   assert(hdValidatePath(path), 'Invalid derivation path');
 
-  return naclKeypairFromSeed(
-    path
-      .split('/')
-      .slice(1)
-      .map((n) => parseInt(n.replace(/'$/, ''), 10))
-      .map((n) => (n < HARDENED) ? (n + HARDENED) : n)
-      .reduce((x, n) => ledgerDerivePrivate(x, n), ledgerMaster(mnemonic, password))
-      .slice(0, 32)
-  );
+  const parts = path.split('/').slice(1);
+  let seed = ledgerMaster(mnemonic, password);
+
+  for (const p of parts) {
+    const n = parseInt(p.replace(/'$/, ''), 10);
+
+    seed = ledgerDerivePrivate(seed, (n < HARDENED) ? (n + HARDENED) : n);
+  }
+
+  return naclKeypairFromSeed(seed.slice(0, 32));
 }
diff --git a/packages/util-crypto/src/hd/validatePath.ts b/packages/util-crypto/src/hd/validatePath.ts
index b0f928f1a..aa5cc19c6 100644
--- a/packages/util-crypto/src/hd/validatePath.ts
+++ b/packages/util-crypto/src/hd/validatePath.ts
@@ -10,9 +10,15 @@ export function hdValidatePath (path: string): boolean {
 
   const parts = path.split('/').slice(1);
 
-  return parts.every((n) => /^\d+'?$/.test(n)) && (
-    !parts
-      .map((n) => parseInt(n.replace(/'$/, ''), 10))
-      .some((n) => isNaN(n) || (n >= HARDENED) || (n < 0))
-  );
+  for (const p of parts) {
+    const n = /^\d+'?$/.test(p)
+      ? parseInt(p.replace(/'$/, ''), 10)
+      : Number.NaN;
+
+    if (isNaN(n) || (n >= HARDENED) || (n < 0)) {
+      return false;
+    }
+  }
+
+  return true;
 }
diff --git a/packages/util-crypto/src/key/extractPath.ts b/packages/util-crypto/src/key/extractPath.ts
index ffe07c423..d757243e6 100644
--- a/packages/util-crypto/src/key/extractPath.ts
+++ b/packages/util-crypto/src/key/extractPath.ts
@@ -23,9 +23,9 @@ export function keyExtractPath (derivePath: string): ExtractResult {
   if (parts) {
     constructed = parts.join('');
 
-    parts.forEach((value: string): void => {
-      path.push(DeriveJunction.from(value.substr(1)));
-    });
+    for (const p of parts) {
+      path.push(DeriveJunction.from(p.substr(1)));
+    }
   }
 
   assert(constructed === derivePath, () => `Re-constructed path "${constructed}" does not match input`);
diff --git a/packages/util-crypto/src/key/fromPath.ts b/packages/util-crypto/src/key/fromPath.ts
index 66143f603..0a2125211 100644
--- a/packages/util-crypto/src/key/fromPath.ts
+++ b/packages/util-crypto/src/key/fromPath.ts
@@ -18,8 +18,11 @@ const generators = {
 
 export function keyFromPath (pair: Keypair, path: DeriveJunction[], type: KeypairType): Keypair {
   const keyHdkd = generators[type];
+  let result = pair;
 
-  return path.reduce((pair, junction): Keypair => {
-    return keyHdkd(pair, junction);
-  }, pair);
+  for (const junction of path) {
+    result = keyHdkd(result, junction);
+  }
+
+  return result;
 }
diff --git a/packages/util/src/array/flatten.ts b/packages/util/src/array/flatten.ts
index 3160e7e98..06b55629b 100644
--- a/packages/util/src/array/flatten.ts
+++ b/packages/util/src/array/flatten.ts
@@ -20,15 +20,19 @@
  */
 export function arrayFlatten <T> (arrays: T[][]): T[] {
   // pre-allocate based on the combined size
-  const output = new Array<T>(arrays.reduce((length, array) => length + array.length, 0));
+  let size = 0;
+
+  for (const a of arrays) {
+    size += a.length;
+  }
+
+  const output = new Array<T>(size);
   let index = -1;
 
-  for (let a = 0; a < arrays.length; a++) {
-    const array = arrays[a];
-
+  for (const a of arrays) {
     // instead of pushing, we just set the entries
-    for (let e = 0; e < array.length; e++) {
-      output[++index] = array[e];
+    for (let e = 0; e < a.length; e++) {
+      output[++index] = a[e];
     }
   }
 
diff --git a/packages/util/src/array/range.ts b/packages/util/src/array/range.ts
index 7e95314b4..f048b7662 100644
--- a/packages/util/src/array/range.ts
+++ b/packages/util/src/array/range.ts
@@ -21,5 +21,11 @@ import { assert } from '../assert';
 export function arrayRange (size: number, startAt = 0): number[] {
   assert(size > 0, 'Expected non-zero, positive number as a range size');
 
-  return new Array(size).fill(0).map((_, i) => i + startAt);
+  const result = new Array<number>(size).fill(0);
+
+  for (let i = 0; i < result.length; i++) {
+    result[i] = i + startAt;
+  }
+
+  return result;
 }
diff --git a/packages/util/src/bn/max.spec.ts b/packages/util/src/bn/max.spec.ts
index 2481a58df..cf477e57d 100644
--- a/packages/util/src/bn/max.spec.ts
+++ b/packages/util/src/bn/max.spec.ts
@@ -9,4 +9,10 @@ describe('bnMax', (): void => {
       bnMax(new BN(1), new BN(2), new BN(3))
     ).toEqual(new BN(3));
   });
+
+  it('finds BN maximum', (): void => {
+    expect(
+      bnMax(new BN(2), new BN(3), new BN(1))
+    ).toEqual(new BN(3));
+  });
 });
diff --git a/packages/util/src/bn/min.spec.ts b/packages/util/src/bn/min.spec.ts
index be3374c32..194b1419e 100644
--- a/packages/util/src/bn/min.spec.ts
+++ b/packages/util/src/bn/min.spec.ts
@@ -6,7 +6,7 @@ import { BN, bnMin } from '.';
 describe('bnMin', (): void => {
   it('finds BN minimum', (): void => {
     expect(
-      bnMin(new BN(1), new BN(2), new BN(3))
+      bnMin(new BN(2), new BN(1), new BN(3))
     ).toEqual(new BN(1));
   });
 });
diff --git a/packages/util/src/bn/util.ts b/packages/util/src/bn/util.ts
index 384a11d8d..ac9f49f93 100644
--- a/packages/util/src/bn/util.ts
+++ b/packages/util/src/bn/util.ts
@@ -7,5 +7,11 @@ import { BN } from './bn';
 export function checkMaxMin (type: 'max' | 'min', items: BN[]): BN {
   assert(items.length >= 1, 'Must provide one or more BN arguments');
 
-  return items.reduce<BN>((a, v) => BN[type](a, v), items[0]);
+  let result = items[0];
+
+  for (const v of items) {
+    result = BN[type](result, v);
+  }
+
+  return result;
 }
diff --git a/packages/util/src/logger.ts b/packages/util/src/logger.ts
index 554a3e48f..6bbc883e7 100644
--- a/packages/util/src/logger.ts
+++ b/packages/util/src/logger.ts
@@ -24,11 +24,13 @@ const logTo = {
 
 function formatOther (value: unknown): unknown {
   if (value && isObject(value) && value.constructor === Object) {
-    return Object.keys(value).reduce((result: Record<string, unknown>, key): Record<string, unknown> => {
-      result[key] = loggerFormat(value[key]);
+    const result: Record<string, unknown> = {};
 
-      return result;
-    }, {});
+    for (const k of Object.keys(value)) {
+      result[k] = loggerFormat(value[k]);
+    }
+
+    return result;
   }
 
   return value;
diff --git a/packages/util/src/versionDetect.ts b/packages/util/src/versionDetect.ts
index 2f7e7a106..ff061f29b 100644
--- a/packages/util/src/versionDetect.ts
+++ b/packages/util/src/versionDetect.ts
@@ -44,7 +44,13 @@ function getEntry (name: string): VersionPath[] {
 }
 
 function getVersionLength (all: { version: string }[]): number {
-  return all.reduce((max, { version }) => Math.max(max, version.length), 0);
+  let length = 0;
+
+  for (const { version } of all) {
+    length = Math.max(length, version.length);
+  }
+
+  return length;
 }
 
 /** @internal */
diff --git a/packages/x-randomvalues/src/node.ts b/packages/x-randomvalues/src/node.ts
index f23f7b901..3a43afd4d 100644
--- a/packages/x-randomvalues/src/node.ts
+++ b/packages/x-randomvalues/src/node.ts
@@ -5,10 +5,12 @@ import crypto from 'crypto';
 
 export { packageInfo } from './packageInfo';
 
-export function getRandomValues <T extends Uint8Array> (arr: T): T {
-  return crypto.randomBytes(arr.length).reduce((arr, value, index) => {
-    arr[index] = value;
+export function getRandomValues <T extends Uint8Array> (output: T): T {
+  const bytes = crypto.randomBytes(output.length);
 
-    return arr;
-  }, arr);
+  for (let i = 0; i < bytes.length; i++) {
+    output[i] = bytes[i];
+  }
+
+  return output;
 }
diff --git a/packages/x-randomvalues/src/react-native.ts b/packages/x-randomvalues/src/react-native.ts
index 01d44bc0b..c111b2a99 100644
--- a/packages/x-randomvalues/src/react-native.ts
+++ b/packages/x-randomvalues/src/react-native.ts
@@ -19,18 +19,18 @@ interface RNExt {
   }
 }
 
-function getRandomValuesNative <T extends Uint8Array> (arr: T): T {
-  return Buffer
-    .from((NativeModules as RNExt).RNGetRandomValues.getRandomBase64(arr.length), 'base64')
-    .reduce((arr, byte, index): T => {
-      arr[index] = byte;
+function getRandomValuesNative <T extends Uint8Array> (output: T): T {
+  const bytes = Buffer.from((NativeModules as RNExt).RNGetRandomValues.getRandomBase64(output.length), 'base64');
 
-      return arr;
-    }, arr);
+  for (let i = 0; i < bytes.length; i++) {
+    output[i] = bytes[i];
+  }
+
+  return output;
 }
 
-function getRandomValuesGlobal <T extends Uint8Array> (arr: T): T {
-  return crypto.getRandomValues(arr);
+function getRandomValuesGlobal <T extends Uint8Array> (output: T): T {
+  return crypto.getRandomValues(output);
 }
 
 export const getRandomValues = (
diff --git a/packages/x-textdecoder/src/fallback.ts b/packages/x-textdecoder/src/fallback.ts
index 97ddcd475..24b2118ac 100644
--- a/packages/x-textdecoder/src/fallback.ts
+++ b/packages/x-textdecoder/src/fallback.ts
@@ -9,8 +9,12 @@ export class TextDecoder {
   }
 
   decode (value: Uint8Array): string {
-    return value.reduce((str, code): string => {
-      return str + String.fromCharCode(code);
-    }, '');
+    let result = '';
+
+    for (const c of value) {
+      result += String.fromCharCode(c);
+    }
+
+    return result;
   }
 }