Here is one I recently stumbled upon in the documentation for IEx:

export ERL_AFLAGS='-kernel shell_history enabled'

This enables IEx shell history between sessions.

I am a sucker for shortcuts, so have just added these:

alias mixec="mix ecto.create"
alias mixem="mix ecto.migrate"
alias mixps="mix phx.server"
alias iexmixps="iex -S mix phx.server"
alias iexsmix="iex -S mix"
alias iexs="iex -S mix"
alias mixpr="mix phx.routes"

I also have various others, such as:

PS1="[\W]\$ "
alias ll="ls -lahG"

alias code="cd /Users/Aston/projects/code"
alias home="cd /Users/Aston"
alias oss="cd /Users/Aston/projects/oss"
alias desktop="cd /Users/Aston/desktop"
alias some_project_name="cd /Users/Aston/projects/code/some_project_name"

alias showhidden="defaults write com.apple.finder AppleShowAllFiles -boolean true ; killall Finder"
alias hidehidden="defaults write com.apple.finder AppleShowAllFiles -boolean false ; killall Finder"

vscode () { VSCODE_CWD="$PWD" open -n -b "com.microsoft.VSCode" --args $* ;}

Plus various others to shh to a server, upload/download files to/from a server, push certain scripts or rsync sites etc

Most of the time I use plugins from Sublime Text or Neovim to interact with Git, but here are a few aliases and functions.

# Aliases
alias nv="nvim"

alias g="git"
alias ga="git add"
alias gaa="git add --all"
alias gb="git branch"
alias gc="git commit -m"
alias gca="git commit -a -m"
alias gcl="git clean -fd"
alias gcm="git checkout master"
alias gco="git checkout"
alias gcp="git cherry-pick"
alias gd="git diff"
alias gfo="git fetch origin"
alias ggpull="git pull origin $(git_current_branch)"
alias ggpush="git push origin $(git_current_branch)"
alias ghh="git help"
alias gl="git log"
alias gm="git merge"
alias gmom="git merge origin/master"
alias gp="git push"
alias gr="git reset"
alias grb="git rebase"
alias grh="git reset --hard"
alias gst="git status"
alias nah="git reset --hard && git clean -df"

alias mr="mix run"
alias mt="mix test"
alias ism="iex -S mix"
alias mdc="mix deps.clean"
alias mdg="mix deps.get"
alias mec="mix ecto.create"
alias mer="mix ecto.reset"
alias mes="mix ecto.setup"
alias mpr="mix phx.routes"
alias mps="mix phx.server"

# Functions
function zshconfig {
    nvim ~/.zshrc
    source ~/.zshrc
    echo "ZSH config was reloaded."
}

function gclone {
    git clone "https://github.com/${2:-$(whoami)}/$1.git"
}

function ginit {
    git init
    git add --all
    git commit -m ${1:-"Init repo"}
}