A single green mana to regenerate your elves is a sweet deal, especially if you have Elvish Archdruid or Circle of Dreams Druid on the field who allow you to protect them all
If you crack 100 FIN packs, you'll end up on average with around 21 FCA uncommons, about 10 FCA rares, and just 2 or 3 FCA mythics
If you want to see just how crazy it can get, though, definitely give Jeskai Dan Polymorph a whirl, turning your UW Doctor (Likely 1st or 11th) into Firion from the deck
This is a big, swingy card that's going to help you win, but before you get there, it also provides a value engine to build up your board state
Even some of those little art cards you toss by the wayside when you're cracking booster packs are going for a pretty penny
In addition to being oversized its also got three keywords and a stack of abilities