Search Homebrew formulae with FZF. Just put the script somewhere in your $PATH and call via "brew isearch".

brew-isearch

#!/usr/bin/env zsh

traverse()
{
    find "$1" -regex ".*\.rb" | while read line; do
        echo $line:t:r
    done
}

traverse "$(brew --prefix)/Library/Taps" | fzf --preview 'brew info {}'