Sneak and ninjutsu usually aim to get creatures onto the battlefield at a cheaper cost
I already mentioned the two cards that deal best with split second cards, but I'm sure you can find others
The Forgotten Realms, for example, has every fantasy trope we could ever need when making a Magic set
MTG isnt really built to allow for this physically (the ill-advised experiment with stickers in Unfinity notwithstanding), so this is a virtual change only that needs to be remembered by all players or signaled with a reminder or a written note
You wont see much traction on TCGPlayer without a full shop on the site, but anyone can list goods on eBay
Its sorcery speed, so you cant pull a removal on an opponents turn, but when it comes to you, if you have the mana, you can get out of any bind with this card