Tribunals get to keep vigilance, wanted and special guards when they do not have scales. They will lose all the other powers(I'm not sure about deputize, though), though. Other powers I can think of are manacles, pillar(the Tribunal pillars that are invoked to transport you between Spire and your city) and judge. Informant was broken when I had it with my trib Agantas, so I don't know about that one either.