現時点の情報量は ls よりも exa を使おう！モダンな Linux コマンド達を紹介 - Qiita　と大差ないうえに解説する気ゼロ。

coreutils

本家 Coreutils - GNU core utilities

by rust-lang

• drrb/rust-coreutils
• uutils/coreutils: Cross-platform Rust rewrite of the GNU coreutils
• gsingh93/rust-coreutils: Implementations of tools from the coreutils package in Rust

by go-lang

• ericlagergren/go-coreutils: A cross-platform port of GNU's coreutils to Go
• aisola/go-coreutils: An attempt at a Go implementation of the GNU Coreutils.
• uiri/coreutils: GNU Coreutils written in Go

by nim-lang

• def-/nim-small-coreutils: Coreutils that compile into tiny binaries

busybox

• 本家 BusyBox

• chingjun/rustybox: Rustybox is something like busybox, but written in Rust language.
  せっかくbusyboxだからバイナリサイズの確認しようと思ったらrustc 1.14.0が通らねえ....

ls

• ogham/exa: A modern version of ‘ls’.

cat

• sharkdp/bat: A cat(1) clone with wings.

grep

• BurntSushi/ripgrep: ripgrep recursively searches directories for a regex pattern

find

• sharkdp/fd: A simple, fast and user-friendly alternative to 'find'

mv

• 拙作 :) Nimの練習がてら、ファイル移動cliを作ってみた - Qiita github

od？

• sharkdp/hexyl: A command-line hex viewer