neon tetras
color glass fish
platies.
guppies
a few sucking fish
I'm sorry to be a party pooper, but if your tank is only about 12.5 gallons, you will not be able to fit all those fish in there, and have them lead healthy lives. The schooling fish, neons and glassfish, would like to be in groups of 6 or more. Platies like to be in a ratio of 1 male and 2 females, as do the guppies. The neons, will probably nip the fins of the guppies. The only sucking fish that would fit in a tank your size is an otto, and they like to be in groups of at least three, but preferable more. Ottos also like mature tanks, that is, tanks that have been running without problems for at least six months. That means cycled for six months. As mentioned already, guppies and platies are livebearers and the females will basically arrive pregnant and ready to drop 10-30 fry every month for about 5 months or so, and if there's a male...Well then, I guarantee, you'll have babies every month for the lifespan of the female fish. In addition, deep breath for me, glassfish, correct me if I'm wrong, are idealy a brackish water fish, if memory serves, and neons and sucking fish are most certainly not brackish. That probably explains why glassfish look so crummy in most LFS, apart from the fact that they are dyed. So unfortunate really, since glassfish can be stunning when kept in their ideal conditions and really have lovely coloring. Why do people insist on improving what has already been made ideal, I'll never know?
Having said this, your tank is small. I would go for a nice school of 1 species of small, slim-bodied, hardy fish. When I say school, I mean 6 fish. If you'd like, you can have a small shoal of one of the small varieties of corydoras, like 3-4, preferable 4. If there's room, and you have algae issues, a small group of ottos, would be great. The ottos should be put last after the tank matures. If algae is not a problem, you can increase the schooling fish to 8. If you add the fish slowly and build the schools, you will have a nice, active aquarium where fish occupy all levels of the tank. There are droves of fish species that fit this bill perfectly. Do a little research and see what tickles your fancy.
I'm sorry I was a party pooper, but your stocking would have possibly led to disaster.