There is currently no good way to fetch the list of all configured user source profiles from a script. From gateway scope, you could use this for now, but just know it depends on internal data structures which (though not likely to change in the foreseeable future) may change:
from com.inductiveautomation.ignition.gateway import IgnitionGateway
from simpleorm.dataset import SQuery
from com.inductiveautomation.ignition.gateway.user import UserSourceProfileRecord
query = SQuery(UserSourceProfileRecord.META).ascending(UserSourceProfileRecord.Name)
results = IgnitionGateway.get().getPersistenceInterface().query(query)
userSourceProfileNames = []
for result in results:
userSourceProfileNames.append(result.getName())
return userSourceProfileNames