There are a lot of materials that you can use as reference, such as the games, the anime, the toys, and the TCG cards
Karn, Scion of Urza has been falling as well since it seems to be merely a very good card instead of a silly broken mistake like so many people (including myself) assumed it was early in the format
But if you have to move Gloom into the active Pokemon spot before evolving it into Vileplume, or you moved Oddish into the active Pokemon spot and evolved it into Gloom, I would always use Poison Powder as long as you have three energy cards on Gloom
When I was looking for one of the remaining Modern Horizons 2 legendary creatures to write about, I hadn't expected to find Chatterfang, Squirrel General still available
For example, Beast Tragic Hero is a Floodborn character that shows what would happen if he never broke his curse and remained a beast forever