When a monster effect is activated on the field or a Normal Spell/Trap Card is activated: You can detach 1 material from this card
If you bump into a player using a terrific card sleeve that you cant find in the store, it's probably a cosmetic thats no longer available (sometimes it may show up again on the store, but only Wizards knows when that may happen)
We may not get to do it every turn, but we shouldnt need to very often
Because the words "choose one" don't actually appear (and because they do not share a mana cost), split cards are not technically modal cards and thus get their own category
You can always head to Reddit, with the thriving r/custommagic community welcoming every design, from the meme-iest joke cards to the most serious attempts at making something that could conceivably be a Magic card
The packs feature reprinted