IIRC Vimium was the one that was pure hotkeys, no commands. Waaay back when Vimperator died with Firefox Quantum, I tried a bunch of different addons that still worked and Vimium was probably the least powerful of them.

Currently I use Vim Vixen[0]. It's still nowhere near as feature-full as Vimperator was, but nothing can be nowadays. My only real complaint about it is how link hints don't let you complete with the link text like Vimperator could - it's the one thing that as far as I can tell, no replacement supports even though it's a whole lot better.

[0] https://addons.mozilla.org/en-US/firefox/addon/vim-vixen/