Starlight Glimmer (My Little Pony: Friendship Is Magic)
Twilight Sparkle (My Little Pony: Friendship Is Magic)
Annie Leonhart (Attack on Titan)
Diamondhead (Ben 10)
Diaspro (Winx Club)
Rhombulus (Star vs The Forces of Evil)
Soul Caliber (Soul Caliber); to the entire world
Master Emerald (Sonic the Hedgehog)
Princess Zelda (The Legend of Zelda) trapped in crystal by Ganondorf.
Chaos (Sonic the Hedeghog), was imprisoned in the Master Emerald by Tikal for thousands of years until Dr. Eggman, having read ancient tablets describing the fall of the Echidnas and Chaos, released it by shattering the Master Emerald.
King Sombra (My Little Pony: Friendship Is Magic) traps Twilight Sparkle in a ring of black crystals.
Starlight Glimmer (My Little Pony: Friendship Is Magic) traps Twilight Sparkle and Spike in a crystal block.
Annie Leonhart (Attack on Titan) has encased herself in a crystal.
Spyro (The Legend of Spyro) has encased himself, Cynder, and Sparx in crystal.
Soul Calibur (Soulcalibur) is very dangerous to freeze the entire world in crystal.