zsh comes with help (set the $HELPDIR)
zsh helpfully comes installed with help files for all the builtins and a run-help command to help you access those help files. There is a trick though, before setting any environment variables here's what happens:
$ run-help
There is no list of special help topics available at this time.
This is because the HELPDIR isn't set. You have to find the install location for zsh's help files and set the env var to that dir. On my system that looks like this:
export HELPDIR='/usr/share/zsh/help'
Then when you run run-help you should see a list of builtins for which there is help documentation. This is the same documentation that you can get via man builtins but much more readable and discoverable. run-help will call man as well if it can't find you're arg in the help files.
For me run-help is cumbersome to type so I alias it. Here's what goes into my .zshrc:
export HELPDIR='/usr/share/zsh/help'
alias help=run-help
zsh is now much more helpful!