Juggernaut (Marvel Comics) Only had to touch the Gem of Cytorrak to initially receive his powers, not needed afterwards.
Various Lantern Corps (DC comics); each have rings that provide various themed abilities.
Alan Scott (DC Comics); via magical power ring and lantern.
Amazo (DC Comics); via copying Green Lantern's Power Ring.
Shocker (Marvel Comics); via his gauntlets
Mysterio (Marvel Comics); via his tech and special effects
Dr. Octopus (Marvel Comics); via his tentacles
Green Goblin (Marvel Comics); via his tech.
Falcon (Marvel); flight via his wing harness
Captain America (Marvel); via the Super Soldier Serum
Black Cat (Spider-Man: The Animated Series); via Super Soldier Serum
Star Girl (DC Comics)
Star Man (DC Comics) (2nd)
Ben Tennyson (Ben 10); via the Omnitrix/Ultimatrix
Guardians of the Temples (Legend of the Dragon); via Powerbands
Thor (Marvel); via Mjolnir.
Captain Marvel (Marvel); via Kree Nega-Bands
Rhino, Scorpion, Shocker, Dr. Octopus, Venom, Carnage, and Vulture (Spider-Man, Marvel); via their costumes
Thanos, then Adam Warlock (Marvel); via the Infinity Gauntlet.
Dio Brando (JoJo's Bizarre Adventure); via the Stone Mask
Mandarin (Marvel); via his 10 magical rings.
Noah/Grimoire (Soul Eater); via the Book of Eibon
Mala Mala Jong (Xiaolin Showdown)
Will Vandom (W.I.T.C.H.); as keeper of the mystic Heart of Candracar
Trixie Lulamoon (My Little Pony: Friendship is Magic)
Lyra Belaqua (His Dark Materials); via Alethiometer
Will Parry (His Dark Materials); via Subtle Knife
Kratos (God of War); via various weapons and accessories (most notably the Blades of Chaos/Athena/Exile). It should be noted that Kratos is also granted innate, magical powers over the course of his storyline by various gods and other entities.
Shinnok (Mortal Kombat); via his amulet
Sonic characters (Sonic The Hedgehog); via the seven Chaos Emeralds
Link (Legend of Zelda); via his Triforce of Courage
Zelda via her Triforce of Wisdom (Legend of Zelda)
Ganondorf Dragmire (Legend of Zelda); via his Triforce of Power
Keyblade wielders (Kingdom Hearts); via respective Keyblades