Harmonic Divine States (Horizon In The Middle of Nowhere)
City of Stone (Rewrite)
Doctor (Black Cat) creating his Warp World, which he can control to his likings, and is virtually invincible while inside. However, he cannot directly control any people or object who came from the outside world.
Espada (Bleach) use Caja Negación to entrap their subordinates in an alternate dimension field for eternity as punishment, but Espada themselves can break free, given enough time.
Yukio Hans Vorarlberna (Bleach) using Digital Radial Invaders to create "chat-rooms", enclosed pocket dimensions that he can freely manipulate and cannot be broken open except by intense powers.
Wandenreich (Bleach) created a pocket dimension inside the shadows of Seireitei, known as the Schatten Bereich, to hide their empire next to their sworn enemy's stronghold.
Road Kamelot (D.Gray-Man) creating her Dream pocket dimension that she has absolute control, and can hide her true form inside, while projecting a duplicate to interact outside.
Garlic Jr. (Dragon Ball) opens the Dead Zone, a dimensional void of absolute darkness that nothing can survive, save his immortal self, which led his eternal and ironic entrapment.
Kaguya Ōtsutsuki (Naruto) has created six personal dimensions, each of which she can control and rewrite their aspects and shift between each one via her Amenominaka.
Jora (One Piece) uses her Heaven's Do Art to create a pocket dimension invisible to the outside world, trapping her foes within and controlling all the artistic creation within.
Tōhō Fuhai (Rosario + Vampire) created a pocket dimension, accessed via a small pool, complete with an entire city, for training purposes.
Alucard (Rosario + Vampire) created a pocket dimension for Kuyō to use to entrap Tsukune and Ruby in an ever-raising inferno that only Kuyō could escape from a prepared portal.
Makora (Samurai Deeper Kyō) using Kage Ochi to drag his victims into a shadow-based pocket dimension for eternity, with nothing but complete darkness until death.
Dimentio (Super Paper Mario) is the master of dimensions, and even created his own Dimension D, which amplifies his strength by 256 (though also unintentionally doing the same for his enemies).
Wall Demon (Valkyrie Crusade) has her own personal dimension/space inside her wall.