If I chose to pin some characters there according to my standards it'll be
Mario by ShinRyoga
Bowser by k6666orochi
Mario by k6666orochi
Kamek by Neo-Kamek
Luigi by k6666orochi
Peach by EugeneQ
In that order of priority. Not sure about those others yet.
Mario and Kamek are classic iconic characters especially on AK1's channel. The k6666orochi characters have an overall better visual quality for AK1 to use in videos. While Peach is only a beta character, it's truly the best Peach we've got right now. Peach also happens to be an iconic Mario character in general. Wario by Warner and Yoshi by Mike or whoever it was that didnt make an 18+ edit can be honorable mentions but not neccessarily in that list for me.