I don't; I'd usually get them from sites like Game Copy World, where they host savegames and no-CD exes too. Still want to scan stuff before running, but I remember that being a pretty good source in the 2000s.

A pretty reliable source (also for new trainers) is flingtrainer.com (there is also wemod bullshit, but at least the individual trainers are still downloadable). Never had any problems with them, they also work reliably on Linux.

Apart from that, gamecopyworld is your friend.

I dont know if its still a thing but megagames used to have trainers.

Depending on what you want from your trainers. Like a Money or anything you can really see the number for. Running a program like ArtMoney or CheatEngine is very doable, and looks harder then it is. You can do it without seeing the actual numbers as hell its just a bit harder IMO.