My favorite is git h, which produces a nicely summarized log of commits on the current branch, with some highlighting and relative dates:

[alias]
    h = log --graph  --abbrev-commit --date=relative --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset'

What’s your favorite Git alias?