Is there a reason to keep common hybrids around?

My park has just run out of room for habitats, so I'm wondering if I should sell my common hybrids for room for more rare hybrids, or if there is a purpose in keeping them.

Solution 1:

Common hybrids are pretty easy to breed so you can easily sell them, the benefit to keeping them is for upgrading the element statues that track your dragons (they upgrade at 50 owned level 10/15 dragons and again with an elder dragon) the statue will keep track or the dragon even if you sell them but unless every stage is unlocked you'll have to relevel new dragons to the same level. You can store dragons in the hibernation chamber (which can be upgraded to hold more dragons for gems). You and also purchase additional habitats in the habitat menu (at the top of the screen) for a gem cost.