Sunflora is already notoriously not a very good pokemon, but if you were to use it in its debut games of GSC, the best Grass-type move it would have access to for a good while would be Razor Leaf at Level 10, replacing Sunkern's Mega Drain.
The lowest level you can catch Sunkern is 11.
Unfortunate.

Hippopotas and Hippowdon both cannot learn Dig through either Level Up or TM in Pokemon Diamond, Pearl and Platinum, despite digging through sand and being caught in the same area where the Dig TM can be found.
This was rectified in HGSS, so I can only assume they genuinely just forgot lmao

using the avalance tm on my sneasel i accidentally taught Surf then evolving it at exactly level 49 to get the most optimal palette of dogshit options

Looked it up and to get a better ice type move on Weavile in DP, you need to

•use a heart scale to teach Ice Punch to a male Medicham
•breed that with a female Buneary (or Lopunny) and hatch a male Buneary knowing Ice Punch
•breed that male Buneary with a female Sneasel (or Weavile)

Steven Stone, esteemed Champion of the Hoenn region, when he drops his pathetic bulky fossil for a real offensive Rock-type powerhouse in the rematch.

In generation 4, Sneasel can only learn one physical Ice-type move through Level Up, that being Ice Shard with its mere 40 base power as its very last move. In addition, should you choose to evolve it into Weavile, it would instead learn Dark Pulse, running off of that iconic 45 SpAtk. Intriguing.