I would suggest to add a dragon market.

On that market, players can offer orbs and/of eggs to other players and put a price on it ( gems, food, joker orbs, ... )

All players can Acces that market and have some market slots. Putting something on the market cost1, gem, second slot 2 gems ...

The trading essences can also be used

Example of offers van be :
50 orbs of Boulders dragon tot 75 gems
25 high winter orbs for 20 heroic joker orbs
1 rare dragon egg for 1.000.000 rood
...