there are sites like dafont, 1000fonts and a couple of others.
but pay close attentions on the terms, some are paid, some are free, free for personal use
so not for ingame, and others can be free for commercial use etc.
than you can use it by either changing the font in the file or use YEP_LoadFonts i think.
buut that needs messagecore as well. I dont know if there are other LoadFonts plugin to
load into the game.