Legality depends on the tournament format -- Grim Return can be legal in some formats and banned or restricted in others
Now let's get the Top Ten List kicked off all proper like
Alpharael, Dreaming Acolyte Ancient Excavation Architects of Will Carlo, Suave Schemer Clutch of the Undercity Cyclonus, the Saboteur Dihada's Ploy Dimir Infiltrator Dire Undercurrents Disciple of Deceit Dreadwing Scavenger Emet-Selch, Unsundered Evangel of Synthesis Great Intelligence's Plan Horrid Shadowspinner Jhessian Zombies Kaito Shizuki Kang, Temporal Tyrant Katara, Seeking Revenge Lazotep Chancellor Likeness Looter Locke Cole Mob Lookout Obsessive Stitcher Oskar, Rubbish Reclaimer Perplex Prowler, Clawed Thief Psychatog Psychic Frog Shadowstorm Vizier Soul Ransom Tainted Indulgence The Ancient One Tiger Shark, Abyssal Hunter Tomebound Lich Ultron, Unlimited Unfulfilled Desires Vohar, Vodalian Desecrator
If any of those cards shares a card type with that spell, copy that spell, you may choose new targets for the copy, and each opponent draws a card