These retro artifacts arent Standard-legal like the rest of the set, but they are legal in both Draft and Sealed - where theyre often absurdly powerful yet a lot of fun to play with
Doubling effects are highly dangerous, because now every pump spell does double damage, and there may even be other things that can double the effect again
The downside is that youre committing resources to a single pile, so you open yourself to getting two-for-oned or worse with targeted removal
Brawl Legal Vintage Legal Timeless Legal Commander Legal Pauper Not Legal Oathbreaker Legal Penny Not Legal Toolbox Buy This Card Notes and Rules Information for Crystal Fragments // Summon: Alexander: Each face of a nonmodal double-faced card has its own set of characteristics: name, types, subtypes, abilities, and so on
If you need more scholarly sources, here are all the MTG card types explained
For high-end collectors, Serialized Cards (like the 001/001 One Ring ) have created a new asset class worth millions