Users can create/generate/open a wormhole, a speculative structure linking disparate points in spacetime, through various means, like magic or science-based abilities. One can use wormholes in order to travel from one location or time-period to another.
Starboy (DC Comics) can compress gravitational energy enough to create wormholes into parallel timelines.
Stormbreaker (Marvel Cinematic Universe)
Palpatine (Star Wars Legends) opening a hyperspace wormhole.
Boom Tubes (DC Comics) are extra-dimensional doorways used by the New Gods to move through interstellar distances almost instantaneously by creating a wormhole through space.
Having been given his robotic components from Apokolips technology, Cyborg (DC Animated Movie Universe) is able to use Boom Tubes for his own benefit like Teleportation or even create his own tubes called Hush Tubes which not even Superman can hear them.
Mukuro Hoshimiya (Date A Live) can distort the fabrics of space-time with her Angel to create wormholes.
Herrscher of the Void (Honkai Impact 3rd) summoning dimensional wormholes to swallow incoming missiles.
The Stargates (Stargate franchise) generate an artificial wormhole, allowing for nigh-instantaneous travel between two gates separated across interstellar distances.
Darth Vader (Star Wars) can open a wormhole to use it for Teleportation, but due to being a cyborg, all of his Force Abilities were limited and it is immensely difficult and painful to do so. Such portal is generated by his own castle, which is designed to harness the power of the dark side on Mustafar.
The Wormhole Transporter (Mighty Med) can opens wormholes to any place and time which Kaz and Oliver use in both of the series Mighty Med and the sequel show Elite Force.
Voyd (The Incredibles 2)
Hoopa (Pokemon) can use it rings to summon Portals.