They love some hardcore neckbeard lit rpg (specially the very western ones, as A Song of Fire and Ice vibe), and read a looooooot. Usually the aren't very fond of romance, BL, or even Eastern novel style (Wuxia, Xianxia and JLight Novel), and they might be very vocal about it. Gramatical/spelling errors, inconsistencies or too much 'filler' might get you laying down on a guillotine.
Best part is that, if you intend to self publish through Patreon, they seem to be quite prone to offer their support, specially if you have like 50 chapters stockpiled.
If you write a long western epic litrpg and has a 9 inch thickness skin, I def suggest you give it a try.