Took me about 2 months of mostly nonstop grinding outside of school and sleep (unhealthy I know, I'm much better about it now), but I've obtained 1 of every species of Pokemon in generation 3 (except for New, Celebi, and Jirachi because Mythicals, but I may try learning Glitzer Popping to get those).
Currently working on gen 4 but I thought I'd share (also sorry about the trainer card being sideways I'm not perfect)
by Vegetable_Leek6900