Alfred (https://www.alfredapp.com/) and BetterTouchTool (https://folivora.ai/) really are two of the must-haves for every mac.
My only excuse for using Alfred is Dash (https://kapeli.com/dash), which integrates with Alfred, but these days so does just about every editor i use (including Vim, Emacs and Sublime Text), so i very rarely find myself using Alfred for it anymore.
One tool i do use at lot though is Hook (https://hookproductivity.com/).
Physical function keys are a must-have for every mac imo
Most new Macs come with full-size function keys, including a massive escape key the same size as the tab key. (At least on the en-US layout; can't speak to others.)
> Physical function keys are a must-have for every mac imo
While it wasn't the case for a while, they all do now.
Also four finger press for cmd+`