I try to keep it pretty simple. I use Karabiner for two specific keyboard alterations (swapping : and ;, and mapping cmd+esc to cmd+` for my keyboard without a dedicated ` key). I also use iTerm instead of the built-in terminal. That's about it, at least recently. I do have Rectangle installed but I don't really use it.

Well, I also use Camo so that I can use my iPhone as a webcam, but I'll probably buy a decent webcam soon because I don't want to keep paying the ongoing subscription. (Why is everything a freaking subscription these days ...)

In the past I used the tiling window manager Yabai, but I've gotten away from that recently. It didn't work properly 100% of the time, unfortunately.