Well you're already using Krokorok, so you're using one of the main Pokemon I would suggest.
Someone said Excadrill, who is a very good Pokemon, but you don't really need two Ground types.
Chandelure is a good Pokemon, but you already have a Fire type.
I'd personally suggest Sawsbuck, because with Return and Leech Horn it can do some good STAB damage, plus it learns double kick
This is sort of a gimmick Pokemon that a lot of competitive players like to use, but you could maybe give it a shot.
Catch a Petilil (Modest Nature if you can, or any nature that raises special attack) and make sure it has Own Tempo as its ability. Then teach it Sleep Powder, Quiver Dance, Leech Seed and Petal Dance. It becomes unstoppable.
Archeops is a really powerful flying type if you ever wanna swap out the one you have. His ability makes him risky if he falls below 50% HP, but he's strong so that usually isn't an issue.
I also recommend Galvantula because...well...he's awesome. But most people would recommend Eelektross because he's a pure electric type with Levitate, essentially giving him no weaknesses.
Hope this has helped some.
