I Always Knew You Could Do It!
Carbink C+ --> B-
Haven't really made a VR post in a while because for the most part I think the VR is quite solid, but I do think that this Pokemon is really undersold. I think it's typing fits very well with the metagame, with things like Lilligant, Carracosta, and Lanturn falling out of favor and the general lack of Steel-types. It's easier to fit on teams than one might at first expect and it performs its job of securely setting up rocks and checking Fires and Dragons well. It's not perfect, and faces a lot of competition from thing like Regirock and Clefairy, but I still think it's better than all the other C+ mons and as on par with most of the B- ranked mons.
Victreebel C+ --> C
Not that I want to crowd the C Rank more than what it's already crowded, but Victreebel is just not that good. I'm probably the last person you'd expect to be making this nomination, but Sun Hyper Offense this generation just cannot keep up. The current metagame is favoring more bulkier playstyles which is the last thing Victreebel wants to hear and recent drops like Aurorus and Spiritomb makes utilizing Sun HO even harder due to Snow Warning and strong priority. Victreebel is still undoubtedly one of the best Special Chlorophyll sweepers of the tier, but Sun being a near irrelevant playstyle prevents this from being any better than what it is.