discrete.EulerDiscreteScheduler,
 diffusers.schedulers.scheduling_pndm.PNDMScheduler,
 diffusers.schedulers.scheduling_ddpm.DDPMScheduler,
 diffusers.schedulers.scheduling_euler_ancestral_discrete.EulerAncestralDiscreteScheduler]
Cool, lots of schedulers to look at. Feel free to have a look at their respective class definitions: 
LMSDiscreteScheduler, 
DDIMScheduler, 
DPMSolverMultistepScheduler, 
EulerDiscreteScheduler, 
PNDMScheduler, 
DDPMSc