I agree, your tank is no where near big enough for rams, clown loaches, or puffers. I like to put clown loaches in groups or at least 3-4, and put them in atleast 125 gallons. Plus, clown loaches get too big for a 10 gallon tank.
Puffers such as green puffers, dont make good community fish, as they may get agressive towards other tank mates.
Rams need ATLEAST 20-30 gallons to be happy. Although I have never personally kept rams, i hear that they are hard to care for, as they are very sensative to pH changes in the water, and they have a short life expectancy.
You already have exciting cool fish! If your tank was larger, I would urge you to get another gourami, and possibly more black phantom tetras. You could try a guppy-only tank. I have one of those. Get one male, and two female, and raise the fry if you want. Guppies are easy to care for and are a great introduction into the aquarium and fish keeping hobby! Try some guppies if you would like. They have lavish tails and are small enough to keep in a 10 gallon community tank, or guppy-only tank. Be carefull not to overstock! With guppies, you could easily overstock your tank. Buy one male, and two female, and raise the fry. Sell some, or give some away to friends who may be in the aquarium hobby. Most importantly, i would like to leave you with this note: ALWAYS make sure that your fish are properly cared for, and to provide the BEST for your fish; so they can live happy lives and provide you with joy for years to come.
Let us know what you decide to do!