I have a plakat betta in one of my planted community tanks. It's 12 gallons but has a very large horizontal footprint so I bend the rules with stocking a bit. It's 36 inches long and about 10 inches high.
6 Glowlight Danio's (very skiddish schooling fish)
2 Red eye Tetra (remnants from a large school I used to have)
3 Sparkling gourami's (normally this is a no-no since they are anabantoids but mine get along with my betta without any issues)
I went with a plakat because the smaller fins are less tempting for tank mates to nibble on and they can swim better in tanks with more water movement.
Here is a pic of my tank.
My 12G Long
For a standard 10g I would go with fish that don't share the same areas of the tank as your betta. Cory's and otto's would probably be a good choice. Small tetras and microrasboras could be a good option too.