Dinkus Mayhem
Lord of Chaos and Despair
"No unworthy living being can lift the hammer from the ground.
People who have lifted it are:
Mainstream (Earth 616)
~Odin
~Captain America
~Beta Ray Bill
~Buri (alias Tiwaz, Thor's paternal great-grandfather)
~Red Norvell (with the aid of gauntlets)
~Eric Masterson (both before and after merging with Thor)
Other
~Superman in Avengers/JLA #4 (2003), but a few pages later he cannot lift it. Explanation was given by Thor that someone might wield Mjolnir shortly if the situation calls for it to happen.
~Wonder Woman in Marvel vs. DC #3 (1996)
~Magni (son of Thor in "Thor, Lord of Earth" future)
~Woden (son of Thor in the Guardians of the Galaxy future)
~Dargo Ktor ("Once and Future Thor" future)
~Ultimate Hulk (in the Ultimate Avengers Movie), Although this version of the hammer has been implied to not be of mystic origins. "
I got that on Wiki: Mjolnir , not sure how accurate it is though.
The only requirement that seems to be followed, is that the person must be a warrior of noble heart and honor. Other than that there is no real pattern I can see, and in the case of Ultimate Hulk it doesn't seem to follow that pattern.
I would be willing to bet that Orion is possibly worthy. True warrior spirit, honorable for sure. In my opinion he could wield the hammer.
Black Panther would most likely be able to lift the hammer as well, he is one of the most honorable and warrior-like characters in marvel and would seem to easily fit the criteria.