Here is a Set of 4 Notecards with Dolphins and perhaps Penguins as the Theme.  

These were published by Tree-Free Cards, and come with light printing inside and matching printed envelopes.

These are all out-of-print and longer available.  Probably rare. 

Upon close examination, one may detect a bit of scuffing on the surface, and hence we call these "seconds."  However, they are still in very good condition and we think a very good deal for such rare items.