For example, if the card you discover has "As an additional cost to cast this spell, sacrifice an artifact," you can't sacrifice one of the Treasures from Hit the Mother Lode to pay that additional cost
Cards have four rarity ratings: Common, Uncommon, Rare, and Mythic Rare
Comprehensive Rules[] 702.81
Adding a color to 8-Rack to improve a matchup or otherwise shore up holes in how the deck plays out probably means that the Modern metagame, or just your metagame in general, isnt soft enough to 8-Rack to be playing it at that moment
You may put that card on the bottom.) Land Land (CTRL to add secondary) Planeswalker Ugin, Eye of the Storms When you cast this spell, exile up to one target permanent that's one or more colors
Especially if youre trying to brew a deck and constantly changing cards around to find the optimal configuration