In Marvel that would seriously be TOAA.
... because to this being (two individuals actually)
everything that takes in the Omniverse from galaxies being obliterated
to Universes imploding to entire Multiverses being reseted in an instant, and so on,
all that,
is just little drawings that one of the individuals that make up TOAA creates,
the other half of TOAA makes up the ideas. (logically the writer)
He/She was defined as "my collaborator" by "God"
who was a senior man just twiddling on an art table, (like an artist)
even Galactus was there (as art) amongst other lower mainstreams on his table.
So therefore, the equivalent of this,
is a being of undeniable supreme power over anything, anything at all,
I mean, the bastards make up and pencil in what everyone is talking about. 😂
There's no comparison.
After that, I would say THOTI and classic Beyonder is a solid debate still.
Then classic Owen Reece. (interesting, shouldn't Owen Reece had been the un-official "supreme being,"😉
since ONLY the Beyonder was above him who was from outside they're Omniverse?)
If so, that would tie him with THOTI imo.
Then the Alien Entity who may also be amongst the "supreme level Gods"
since if the story is followed,
it is the past/present & future rolled into one,
the AE merged with the fires of creation,
basically becoming one with everything from beginning to end.
So that's another debate atleast concerning Owen, and THOTI,
but Beyonder was still from outside all this if we consider the pre-retcon version of the story.
HOM Wanda in another candidate for the top imo.
... anyways. 🙂