On the screenshots of Doom Emacs themes (https://github.com/doomemacs/themes/tree/screenshots) I see the minibufer on the top of the screen with the visual autocomplete: How to achieve this look and feel of minibuffer in vanilla Emacs?
The only addon doing something like this I found is emacs-mini-frame (https://github.com/muffinmad/emacs-mini-frame). In ivy-mode
it shows something slightly similar, but the behavior of emacs-mini-frame in XMonad (the WM I use) is very strange (some problems were fixed with ugly hacks of XMonad config, but some still not).
I searched for «minibuffer» in Doom Emacs repo (https://github.com/doomemacs/doomemacs), but failed to understand, where this look is configured.