You can change the rock type. Stuff like schist or slate has much lower friction than granite.
Supposed "world's hardest slab" 14c in Madagascar is smearing crystals on an almost-vertical granite face; likewise 14a on Half Dome is supposedly 88-89 degrees, just shy of vertical. They may be smearing but it's hard to call something that steep a slab.
On the other hand "The Very Big and the Very Small" 14a/b on Welsh slate is only about 70 degrees in angle, but frictionless smearing and mantling on holds ranging from fingernail to matchstick width.