What is something someone can do to revenge?

I cut my toxic mother out of my life and once or twice weve seen her stalking around our old apartment (I moved).

I doubt she will remember where I work, but I'm scared she might try something drastic since she never got a chance to tell me off as I've blocked her on all social media and phones.

I've not had too much contact with her the last 9 years, but last I was in constant contact she tried to run me over 3 times. I dont want to do a restraining order because I dont think I can even get one since her last real threat was almost a decade ago... plus a restraining order will likely give my address... I just want to be prepared.