I like to use MS Paint to do stuff with vehicles, trains and stuff like that, I also like making emergency vehicle animated stuff, Here are some of my favs that I have done:
I also do some Lego Digital Designer stuff and render them into something a little realistic:
I will also take crudely made CAD drawings, clean them up in MSPaint and use them as templates:
Then I might try to make my own stuff:
Thanks for looking at this topic!