What new grenade types do you want?

So, according to the unbiased facts thread there will be four different types of grenades and you can hold 4 of whichever two you are holding. As Frag grenades and Plasma grenades have already been confirmed, what types of grenades do you want to see? I wouldn’t mind an EMP, a concussion grenade or the return of the fire grenade. Personally I think there should be more than four types of grenades as that would provide a lot more flexibility with loadouts.