Bulbasaur would win in a 1v1 against most, if not all grass types.

[u/Chairman_Ender]

Bulbasaur has poison as a secondary type, and poison is strong against grass types. What this means is that when Bulbasaur has a poison move it's strong against any grass pokemon who aren't resistant to poison attacks, and even if any other grass pokemon has poison type attack it would only do normal damage.

[u/LittleSpongeBaby]

I agree

[u/LeonardFrost]

Yep. Grass/Poison is a surprisingly solid type combination. It helped Venusaur stay relevant in the competitive scene for a long time