is there any vertical incremental completion in Emacs?

[Jean Louis]

I am researching various built-in modes in Emacs so that some
applications do not depend on external packages and that I could later
propose it to ELPA without dependencies on outside packages.

So far I am using helm for reason that it is vertical incremental
(search like) completion, and I would like to simplify it. I would
need split window or full window and list of possible completions in
similar manner as helm, but not fully. Plethora of applications are
possible to be built on such, I don't speak of tools but business
applications and I already use them. And it needs to select from large
number of items.

Helm works well but is also overkill.

Maybe something similar already exists?

I am looking into all available built-in packages that contain the
word incremental, icomplete, ibuffer, allout, but I do not find what
would be usable.


-- 
Jean Louis