The largest not tilted rotor is a wind turbine:
And, to my knowledge, the largest tilted rotor running in autorotation (for a gyroplane, the helicopter Mil Mi-26 having a rotor diameter of 32 m):
Main rotor diameter: 90 ft 0 in (27.43 m)
I am thinking more and more the same thing, and that the wind turbine should be non-tilted, not just because of the absence of cosine losses, but considering the overall operation and the stresses on the rotor, which are more balanced since there’s no advancing or retreating blade.
It is not impossible that the very significant difference between the dimensions of a non-tilted rotor (wind turbine) and a tilted rotor can be explained by physics itself and the constraints mentioned above, despite the limits of this explanation due to very different uses.
The quote above could also apply to crosswind kites, because they ensure both power generation (through fly-gen or ground-gen) and lifting, operating on a tilted plane defined by the tether, with a variable elevation angle and varying distances from the more powerful zone of the flight window, with gravity (kinetic energy) issues, undergoing stop and go, hence huge losses in average power.