My old computer had HM Phonetic show up as Greek Letters. I don't know of any others but you have to be careful when using a font that's not as universal as symbol. When I put letters into my profile, I used HM Phonetic, and everyone was im'ing me saying that the font didn't come up on their computers and it looked like I just had KLY instead of KLY in my profile.
You could use HM Phonetic if your computer has it, but HM Phonetic ends up looking exactly like symbol when you type it out. Custom Ink has a bunch of really cool Greek fonts that you can use on their site if you're designing shirts or whatnot, so you could go on their site and look for fonts you like and then try to google them and download them to your comp.