Fine tip markers- find a highlighter that you can pull the bottom out of, clean it out. put something in it to hold your ink/ paint. More fill= less drips. Then, make a nib out of felt, or whatever shit you can stuff in the small hole.
Medium- the basic glue stick dauber shit, same principle as everyones been sayin.
Mops- go to the dollar store, but rollon deoderant and a sheet of felt, cut the top off the deo, clean it out, make your own ink or paint thats thinned, pour that shit in, and roll up a cut up piece of about an inch from your felt sheet after you cut it longways. You might have to fix nib, or use different material for the nib if the paint is too thick. But you get madd drips from this shit if you want it.