The official Japanese Kirby website, Kirby Portal, has just added a new section on Kirby's Copy Abilities! It's an extensive database that details every Copy Ability, including short videos that demonstrate them, and official artwork, some of which have never been seen in good quality up until now.
Not every Copy Ability is added yet, but more will be added over time, including some of the special Copy Abilities like Super Abilities and Hypernova.
Check it out here!