tetras 4 max

Hello,  I am new to this forum and set up a 10 gallon aquarium with currently 1 mystery snail, 1 F. Crowntail betta, 3 black kuhli loaches, 4 endlers and soon 2 ADFs.   My question is: Are there any tetras or other fish that would fit in the tank and can be in schools of 4 if I take out the...