This is a list of the strongest reality warpers that I know of. Characters like Pre-retcon Beyonder, Molecule Man and the Celestials make the list by default. The list is in order from the strongest to the weakest. Let me know if I have missed any, or if the list is not in order. Thankyou!
Note: The list is based on viewed realitty bending powers, not based on the overall power.
Pre-Retcon Beyonder. He isn't just the strongest character in the history of comics, he bends reality according to him, without limit.
Not a conventional reality warper, as he is unable to produce the substance that he is able to manipulate. Similar in ability to MJJ, but Lucifer outclasses MJJ.
Someone that is perhaps the only rival of Pre-Retcon Beyonder, a crazy powerful reality bender that once clashed with Beyonder.
This fifth dimensionl counted among the strongest reality warpers.
Able to dictate reality as he pleases, he is the servent of the one above all.
Psychic Entity with vast degree of control over matter and dimensional physics.
A stronger counterpart of The Monitor.
Spectre is a multiversal being capable of altering reality, only limited by the presense.
Including the team together as one character. They are masters and creators of the known universe. Powerful reality warpers serving a higher source.
Son of Reed Richards, Franklin is a powerful Omega mutant and a reality warper.
The being responsible for the creation of parralel universes.
MJJ is a powerful reality bender, but sometimes cannot control himself
Has been seen altering reality on a planetary scale.
Combination of Professor X and Magneto, Onslaught is a powerful reality bending anomaly.
A reality bender with power over space and time, manipulating it to any end he wished.
A lantern, the first lantern embedded with all the powers of the energy spectrum, able to manipulate reality and peoples lives.
At his most powerful, Genie can grant any wish. A genie has been seen creating a solar system.
An imp copy of Batman from the fifth dimension with powers similar to Mr. Mxyzptlk.
A multiversal demon, and father of Raven, has been shown bending reality on a planetary scale.
The persona of legion known as X is a powerful reality warper.
Proteus can manipulate reality on an almost infinite level.
Upon activating the meta nanites, Rex temporarily gained the ability to manipulate reality.
Alfie has an ability that allows him to observe the multiverse and do changes according to what he see fit. He can alter the course of reality.
A robin from an alternate dimension (possibly from the 5th dimension), with a magical finger that can bend reality. Though, his control over the powers is limited. Trying to fix Robins broken hand, he managed to fix the hand, but sent Robin to a place that looks a lot like Beyond-realm of the Beyonder, with nothing in it. His magical finger breaks during the episode, warping the reallity of Earth beyond recognition, turning most aspects like the sun and buildings into sketches, with sketch monsters roaming the Earth, and made an evil biker a supreme entity.
A reality warper that can animate dead and manipulate matter and energy.
Reality Bending devil fruit ability. Can create a room where he can control reality, defy gravity, spatially displaces anyone and anything caught inside the room.
A mutant with reality warping ability, but can only work in a limited range, particularly in her direct line of sight.
Mikhail has a degree of reality manipulation powers.
low level reality manipulation, used for teleportation means.
Uses a remote that can bring inanimate objects and things to life, commanding them as he pleases.
Has a Bankai that can turn the targets perspective upside down and backwards. It warps the targets reality.
