Fish suggestions for an 8-gallon aquarium?

So my grandmother's boss was dumping their 8 gallon aquarium and upgrading to a 15 gallon. He said they hadn't used it in the past year and it was just taking up space, so needless to say I laid claims on it.

So what are some good fish suggestions? I have done larger aquariums in the past but none recently. I also know nothing about fish species really and who gets along with who. I want to have a small variety for the aquarium. So if anyone knows any interesting small tank set ups I'd love to hear them (with pictures of the suggested fish if possible please).

I'm not making any decisions soon, I want to set the tank up and leave it running for several days. I heard you should do this before putting any fish in the tank. Oh, and it's going to be a freshwater tank set up and it doesn't have a heater so it needs to be fish that don't require heating.