Theres quite a few who are magic. Not many who are full sorcerers

Full sorcery

Saul (external)

Apocalypse

Selene

Pixie

Wiccan (technically a mutant)

Magik (limbo based magic)

Madelyn Prior (limbo magic)

Damian Tryp

Knows magic:

Forge (knows shaman magic)

Warpath (limited shaman magic)

Rictor (limited magic)

Sepna (ability to understand all languages caused her to innately understand magic)

The new Black Knight (mutant who knows limited magic)

Thats most of the ones that come to mind. There might be a few ofthers.

Oh and of course Beast became significant with magic but still low level for most sorcerers. Currently beast still has that knowledge but cant use it without turning himself into an abombination.

Theres also just serveral who arent magic vut have connection to magic.

Like:

Moonstone was a Valkyrie for years, and then was Hela's personal Valkyrie, making her embrace asgardian magic.

Vox Ignis (formerly Banshee) is a spirit of Vengance and a mutant.

Both pixie and Glorianna have magic family roots, both being connected to Fairies through family lianiage.

There is also a special brand of Sorcery on Arakko known as Summoners. Its a highly significant role in arakko culture.

Both Angel and Nightcrawler have links to magic as well.

Nightcrawler being a decendent of the the neyaphem, a demonic subspecies of mutants that lorded over the brimestone dimension. Nightcrawler's dad is essentially the mutant devil, named Azazel. So nightcrawler has magic liniage.

Angel is a decendent of the cheyarafim, an angelic subspecies of mutants whose blood heals people.

But of all the mutants who know magic, known of them get magic directly from their x-gene. So its always mutants who know much, and so far none whose mutation is magic.

For example:

-magik's mutation allowed her to teleport through limbo, where she was trapped and learnt magic.

-sepna is a mutant who speaks all languages, allowing her to understand magic naturally.

-pixie has magic liniage, but her mutation is actually hulucinogneic dust and fairy wings. She gained magic after part of her sould was stolen by Magik in Limbo, which caused her to forge a soul dagger. The remainder of her missing sould was replaced by magic energy, causing her to be magic.

So far there has never been a mutant to my knowledge whose magic powers were a direct expression of their x-gene

The ones I can recall off the top of my head:

Selene

Saul

Candra

Apocalypse (tho he is more of a dabbler then a full on sorcerer)

Madelyn Pryor

Magik

Pixie

Beast (but more of formally then current)

Warpath (some)

Storm (she's not full on yet, but she does have magic potential)