Be able to sell Urgent Quest Triggers or trade them in swap shop

some players such as me dont ever use them because no alliance etc so it would be nice if we could trade or sell them away instead of discarding (which feels like a waste) or filling our storage with them

Triggers will never be sellable due to their high demand for certain enemies. In addition, they count for certain collection folders where urgent quests normally would be counted. If they became able to be sold, they would have to remove the ability for trigger quests to be counted for those.

Join an alliance that runs those, even if you join it temporarily. I don't think many of them will say no to it.