A new feature that would allow guild members to trade mods. Could be directly or via a new currency for black market. A coin type would be used similar to the shards, higher lvl players could sell 3-4 * mods or extras for mainteams, could be done directly trade a 5* triangle for a 5 star triangle of a different main attribute, or simply Auction House type, High rarity mods could be restricted to avoid abuses.
This would add a fun feature in guild (like the mats donations) and would provide an infrastructure for future item addings. It would also help with main teams in the case in wich i want a pure speed mod while having a offense 1 of the same type while a guild mate is in the opposite situation.I think it could be a nice addition and is easily balanced by restrictions