Check out marginalia[1]. Whenever you press M-x, it will pop up a buffer showing all the commands (with most recent ones on top) along with their keybindings and a brief description of what they do.
Embark[2] is also cool. It will show all the possible commands relevant to where the cursor is at that moment. I bind it to C-c a.
I'll usually do C-h f (describe-function), then hit tab to make it build a list of all (interactive) functions, and then switch to that buffer and search for whatever I'm interested in.
[1]https://www.gnu.org/software/emacs/manual/html_node/emacs/Ap...