In which case I'll just tldr my point.Gonna pop in here. We aren't speedrunning if this is what you are implying. The list has already banned the most commonly used Item Combo which is X Accuracy and an OHKO move. As for the fangame, I fail to see any relevance here with that. Additionally, we should not be comparing mons to one another and using that as a condition to tier. The Pokemon should be tested on its own merits. You can compare a mon to make a point or argument, but never when it comes to actually placing them.
Venusaur is by far the worst starter. It requires a TM to even be passable and has the worst boss battle matchups. It's worse than anything else in A tier and is arguably more on par with things in B tier.
Victreebel has very similar stats, a better movepool (despite some awkwardness from level 30-38), is captured at a decent level, and arrives at a time in the game where grass / poison types are decent (Cerulean to Celadon). B tier.
Both Pokemon are definitely better compared to the others in B tier rather than A and C.