They can be dual-typed, but at least one of those has to match the type you choose. What type are you choosing, and what’s your team look like?
I would have to choose Bug-type, of course. Team composition would be Galvantula, Yanmega, Heracross, Centiskorch, Genesect, and Rabsca. As to why… I just like 'em, lol. I’m not much of a competitive player. What would your team/type be?
Dark type. 100% just because I play by the rule of cool and my favourite Pokémon belong to that type. Not sure about the entire team, but Houndoom, Mightyena, and Umbreon would be there for sure.
Strong choices all around. Dark type is definitely in my top five, and I love Mightyena. I think it’s easy to sleep on, since you get access to Poochyena literally right out of the gate, but it’s a seriously tough Pokémon.