When I think of pschye magic I think of thing that mess with peoples minds. could you add a couple new lines of gems
that cause
blindness(timed)
randomly switching around who someone is targeting((one time cast
permanent until the player actively changes it)possibly to allies no afk)
randomly changing the location on screen of everyone's faces.( more like distorting vision causing target changes to be harder if you need to change)
changing images of gems in the slots with out changing the affects of the gems.(one time cast affects a single target(really vision is one of the more easily fooled of the senses))
a "hidden" detrimental aura that gives you the face and weapon set of a random top 25 character(while still maintaining your own).( I know a few people when they see relic or poopoo or flippy or mel or san in arena they don't bother hitting auto attack since they will die anyways) to all those affected. with out changing what you really use.
showing random gem casts from players that your team is facving that seem to do damage but really aren't. (1 player affected their team mates health appears to plummet after a large crit or something) could really do a rank or 2 lower then regular gray DD damages
everything appears blurry and you have half the chance of hitting
detrimental aura of false vitality. all your hits seem to do quite small damage to opponents when really it is normal hits done they see their health bars as dropping slower. it hurts when your healer doesn't know who to heal if everyone thinks they are fine.
Oh and squelches for the duration of arena matches after you die in one so you can not give away what they are using >

I mean really if you died at half health that would suck but if you used the aura of false vitality and the random gem cast that do a large amount fo damage and you reallyed killed them from the real cast damage what could you do >
these are just ideas though
Mobs would be able to cast some of these affects as well.