Now, this, I think, is Oda setting up a Third Power System. To go along with Devil Fruits and Haki.
Because, most of these characters have something in common. They all seem to be using "Symbol Magic".
As we've seen lately, Imu and God's Knights are using the Abyss Marks and Contracts to gain powers and abilities.
Miss Goldenweek's Color Trap involves painting a symbol on their opponent, with different colors having different effects.
On Wano, the Marys use their All-Seeing-Eye face charms in order to form a sort of hive mind together.
Madame Shyarly, if you look VERY closely, has a BUNCH of Eye (or Sun) symbols all over the inside of her hoodie. Which could at least be used to amplify her natural precognitive powers.
Even Estrid's Earth-Wind Arts, which is basically Feng Shui, could be a type of "Symbol Magic". Rearranging furniture and the objects to form different patterns in the environment in your home. Basically, forming a pattern on the ground that didn't exist before.
As for Faust? Um...I guess he has that Cross that he wears? Maybe that's his "Symbol Magic"? (Although, if that is so, I guess that could mean Mihawk is also using "Symbol Magic"?)
In my mind, "Symbol Magic" would be the power of the mind and knowledge. You would need to know how to use it and study it in order to use it properly. Basically, it's alchemy. It would basically be like learning how to code a computer program, but you're learning how to "reprogram" reality. In contrast to Devil Fruits which are the power of dreams and the soul. And Haki which would be the power of willpower and the body. Completing a trinity of mind, body, and soul. I think this Third "Symbol Magic" System could explain all the unexplained instances of "real magic" in the One Piece World. Maybe it's all part of the Abyss, or maybe the Abyss is only a small part of the larger "Symbol Magic" system, but either way, I suspect something's up.
I do think Oda's setting up something with "Symbol Magic". It's appeared often enough in the background that I'm pretty sure it's going to be a real thing in the actual story. But, who knows? I could be completely off base with this.