Check out https://github.com/Valodim/zsh-capture-completion.

I referenced it recently to implement completion suggestions in
zsh-autosuggestions:
https://github.com/zsh-users/zsh-autosuggestions/pull/330

On Wed, Jun 6, 2018 at 11:43 AM Sebastian Gniazdowski <
sgniazdowski@gmail.com> wrote:

> Hello,
> last commit to the project is from 2013 and I cannot get it up and
> running. Is anyone familiar with its method of functioning? A friend
> guesses it pretends <tab> key to be pressed after each character, is
> that true? It would then mean it constantly shows completions under
> prompt. Is using shell this way actually possible?
>
> In general, I'm looking for a method of calling completion functions
> manually and presenting the results in different form. Does someone
> know anything about this problem?
>
> --
> Best regards,
> Sebastian Gniazdowski
>
-- 
Sent from my iPhone