I originally controlled only Blazkrieg, which is usually just four members of the Ouendan, two of which are ZX versions, the two series of Robot Masters, though they're only mentioned and rarely show up for more than one plot and, very rarely, Clef and Tango. But after Tarot Cat, I may have gone overboard despite knowing where the cards in its deck are (figuring out how to have them interact with other characters was another matter).
If I'm going to have Tarot Cat in future RPs or situations, I'll try and keep it down to just five cards (Fool already being inserted and the other four being the Major Arcana representation of the four courts in Tarot cards: Hierophant = Pages, Chariot = Knight, Empress = Queen, and Emperor = King), and the other cards either being momentary cameos or replacing one of the main five for the duration of whatever arc or plot they get involved in. Or, if I decide to just use the Magical Drop characters that inspired Tarot Cat's creations, the cards they might use will only be mentioned but seldom do anything beyond sharing their abilities with the characters who decide to equip them.
The same with Blazkrieg if they show up with Tarot Cat, though it would mostly be Hajime since he was the one who created it and its cards.