I apologise if my idea has been posted previously or is ruled out but I honeslty couldn't be bothered reading the list :P
-Alchemists
Basically builders but used in laboratories.
1st alchemist is free
2nd alchemsit costs 250 gems
3rd alchemsit costs 500 gems
Next to the builder you would have some kind of thing (so much for detail) that'd show the amount of alchemists you have and how many are free (like builders [e.g 2/5]). Probably a picture of a level 6 wizard.



