First printed in Exodus (1998)
Memory Crystal 
Artifact
Buyback costs cost 
less.
Combos
79 combos from Commander Spellbook, the most popular first.
- Infinite magecraft triggers, Infinite red mana…: Memory Crystal + Reiterate + Seething Song
- Infinitely powerful creature until end of turn, Infinite magecraft triggers…: Goldspan Dragon + Memory Crystal + Seething Anger
- Infinite artifact ETB, Infinite artifact LTB…: Memory Crystal + Sculpting Steel + Searing Touch + Storm-Kiln Artist
- Infinite artifact ETB, Infinite artifact LTB…: Memory Crystal + Sculpting Steel + Seething Anger + Storm-Kiln Artist
- Infinite damage, Infinite magecraft triggers…: Memory Crystal + Sculpting Steel + Searing Touch + Urabrask // The Great Work
- Infinite damage, Infinite magecraft triggers…: Birgi, God of Storytelling // Harnfel, Horn of Bounty + Memory Crystal + Sculpting Steel + Searing Touch
- Infinite damage, Infinitely powerful creatures you control until end of turn…: Memory Crystal + Sculpting Steel + Seething Anger + Urabrask // The Great Work
- Infinitely powerful creatures you control until end of turn, Infinite magecraft triggers…: Birgi, God of Storytelling // Harnfel, Horn of Bounty + Memory Crystal + Sculpting Steel + Seething Anger
- Infinite damage, Infinite magecraft triggers…: Electro, Assaulting Battery + Memory Crystal + Sculpting Steel + Searing Touch
- Infinite turns, Lock: Memory Crystal + Sage of Hours + Whim of Volrath
Legality
Constructed
- Standard Not legal
- Pioneer Not legal
- Modern Not legal
- Legacy Legal
- Vintage Legal
- Pauper Not legal
- Future Standard Not legal
- Historic Not legal
- Timeless Not legal
- Alchemy Not legal
- Penny Dreadful Not legal
- Premodern Legal
- Old School 93/94 Not legal
Singleton
- Gladiator Not legal
Commander formats
- Commander Legal
- Duel Commander Legal
- Pauper Commander Not legal
- PreDH Legal
- Tiny Leaders Legal
- Oathbreaker Legal
- Brawl Not legal
- Standard Brawl Not legal
- Competitive Brawl Not legal