>>42981829grass/rock is surprisingly alright. You've got two of the worst defensive typing and somehow both's resistances cover the other's weaknesses well.
Grass nullifies grass/water/ground weakness from rock,
Rock nullifies fire/flying/bug weakness of grass
No 4x weaknesses despite the two having the most weaknesses.
On top that you keep the utility of having a grass type (immune to leech seed, powder moves) and the utility of rocks (immunity to sandstorm and a buff under it for being rock)
