Too many of the same creatures

[Symmetar]

Hello,

I am new to the game and made the mistake of taking too many creature because I was unaware of an important point, to refresh my browser window after clicking.

Is there a way to delete some of the creatures that are not needed?

[Tissy]

No way to delete. You could only sacrifice the creatures to be part of you. 

[Shemhazaj]

is there an altar on Gateway Island?

alternatively you can gift a creature to someone else via CTC code.
perhaps someone who has access to a sacrificial altar.