So I have a male Betta, I've had him since August of 2012, and he's healthy and happy, but I thought, maybe I could buy a tankmate for him. And yes, I know, 1.75 gal. is pretty small, but if there are any fish that could work? So... yeah. That's about it.
Nope Sorry, 1.75 is too small for any tank mates. Now... if you got a bigger tank... like 5 gallons... you could do more
Most smaller fish need 6 other members of their own species, snails produce too much waste, and shrimp would work in that size tank if it didn't have a predator in it they need more space to hide with a betta around
Snails are REALLY messy, they produce a lot of waste, unless your tank is seriously planted with a lot of live fast growing plants and you're willing to do multiple water changes a week, I wouldn't add a snail in a tank that small.
Shrimp and snails mostly. Some people manage a small school of neons or endlers, but fish need more space than a person might think. I was really surprised when I first got into fish keeping about what fish really need.
If you want to have a legit community, go with a 10 gallon or larger, then you could have a good sized shoal or school of fish or bottom feeders like cory cats.