There's this functionality that I have done twenty times in vim but after searching stackoverflow every single time. And that is to edit the beginning of a bunch of lines. You've gotta switch to visual mode, select lines, then do some keys, all so difficult to remember.
I'm trying out helix today and it is the first thing I tried and it is so easy to remember.
Select all the lines you want (you can use x to select lines).
Start substitution with s
Enter regex (^ is what I want)
Do what it is that you want? Change with c, insert with i.