Hi, so sorry for your loss, but it was as I had figured. The important thing now is to learn from your mistakes and not make the same ones again.
There are a number of species of fish you can keep easily in a 2 gallon, but some will require a heater. I will seperate them for you by tropcial and cold water... and please remember, the largest number of any of these fish able to stay in a 2 gallon is 2. All of these fish will also require a filter and a 30% water change once or twice/wk.
The best thing to do now is to let the tank run for a few days, doing a 30% water change each day. If you reach in and stir up the gravel before you remove the 30% each day, you will then get the majority of the waste out of the tank without disturbing the bacteria culture that needs to grow. This will get the tank ready for the new fish. If you have already broken it down, emptied it out, etc... go ahead and fill it up at least 1 - 2 wks before buying more fish. Let all of your equipment run (filter, heater, light) as if there were fish in the tank, just no water changes if the water is all new. 1 piece of flake food every 3 days will add enough ammonia to get the tank started cycling without fish, so you can avoid future issues. Also, please get the test kits, use them... follow as ammonia goes up and then down as nitrite goes up, and then down as nitrate goes up... when you have no ammonia, no nitrite, and a small amount of nitrate, your tank is then cycled and safe to add fish. Now, for a list...
Cold water (limit of 1 - 2 fish total)
white cloud minnows
gold white cloud minnows (these are very bright and pretty fish!)
Tropical (warm/with heater) water (limit of 1 - 2 fish total)
fancy guppies (I would not mix male with female in a tank of less than 25 gallons)
coral platy (this is a dwarf species of platy, bright dk orange, and again, only 2 males together in that size of a tank)
killiefish (if this interest you we'd have to break it down further because some species of killies get too large for a 2 gallon)
green fire tetras
pygmy cory catfish
dwarf frog (limit of 1 per 2 gallons)
dwarf emerald rasbora
There are probably still a few less common (harder to find) that I've forgotten, but there are a lot of options here. Your limit would be 2 fish, and some are mixable. I would suggest hitting the search engines (or ask and I can find you links) and take a look at each of these fish, get a feel for what you like. Once you know what your preferences are, come on back here and post a list and I'll help you sort what is compatible with what. I have done some very unique thing with 2, 5, and 7 gallon tanks, and they've turned out absolutely beautiful with minimal work involved. Most of these fish have life spans of 3, 5 and even up to 10 yrs, so you could have a long term situation quite easily. All of these fish are compatible with live plants, so I will surely encourage that, and as much decoration as you can fit into the tank. Also, if you need help finding a heater to fit into a 2 gallon, let me know and I'll help you online. Hydor makes a small one that looks like a small heating pad, and it works wonderfully.