Bubble nests doesn't always mean happy, just a heads up. Also, the bigger the better! You'll be giving him a new home, and he'll spend some time explorin', he might be uncomfortable for a day or two, but he'll adjust fine.
A 10 gallon opens the door to some fish friends, I would recommend 6 or more Pygmy Cories, they're cute little critters very compatible fish for Bettas, just make sure the substrate you're going to use is sand.
If you're not going to use sand as a substrate, may I suggest Ember Tetras? Small little tetras, cute little buggers, around 6 or more of them would be nice.
If you want a snail I suggest Nerite snails, they can't reproduce in freshwater, they need brackish water. They're also way better algae eaters than Apple/Mystery snails. If you're looking for shrimps they're usually a hit or miss, most Bettas find them as a lovely snack.
If you want shrimp I suggest getting sometype of moss for them to hide in, or some little caves so they can run to safety. Generally moss works, but as I said, hit or miss with shrimps.
Also, tankmates depend on your Bettas temperament. If he's a mean one, he'll have to live alone. ):