Do you mean you had those bettas together???
Well anyways, how big is your tank? If it is at least 5 gallons, than you could probably put a pair of male guppies in there. (Not females or a male and a female, because they will reproduce like crazy!)
Or you could get a couple tetras and a snail or two. (Apple or mystery)
But your tank MUST be at least 5 gallons if you want a different kind of fish/ a fish at all.
Hope this helps!
Good luck!