>>43569160A type combo that was overused in Gen I for various reasons, and still gets memed about to this day despite only two Grass/Poison families being introduced since Gen I (the last one being back in Gen V).
Their numbers are also artificially bloated by all of them being part of a three mon evolution line aside from Amoongus, making the type seem more overused than it actually is. Only 5 fully evolved mons use the type, in comparison there are 7 fully evolved Water/Rock Pokémon, and 6 fully evolved Bug/Steel Pokémon. Casuals will still bitch about Grass/Poison being too cliché though even though that was only really true in Gen I.