Currently you can only see the list of creatures you have bred/hatched. I think it would be useful to be able to also see the list of creatures seen in battle. These creatures could be denoted differently in your library entries. Also you wouldn’t necessarily have to show their base stats (these could be ?? until bred/hatched) but at least show the image and trait associated with the creature (as this is already seen in battle anyways).
It would also be helpful if the breeding combination library took into account these creatures you have seen - and was able to display the projected creature with its trait and visualization (if seen or otherwise owned) - versus just the name of the creature (which requires cross referencing to confirm what it is).