The example job payloads in https://github.com/ASFHyP3/hyp3-docs/blob/develop/docs/using/api.md call out the optional job parameters for each job type, but these have not been kept up to date as new parameters have been added.
As of this writing, options not included in the examples are:
RTC_GAMMA
dem_name
include_rgb
resolution
INSAR_GAMMA