At the beginning of your upkeep, you may put a creature card exiled with Chaos Shrine's Black Crystal onto the battlefield under your control with a finality counter on it
A rarer card will have much less supply, and rare cards are often the ones in demand for Constructed decks since theyre also typically stronger
Draft boosters are identical to traditional 15-card MTG packs, while theme boosters (which previously appeared in Guilds of Ravnica) include 35 cards designed around specific gameplay or lore elements, and collector boosters offer rare and foil cards at a higher cost than the other packs
You also can't play a million tricks though, as you need creatures for your deck to work, so I don't think you can play both
**The library is an abstract representation of a Planeswalkers memories, or ideas waiting to surface
I can cast it whenever I want, such as during my upkeep or during my opponents combat