The fastest option would be to go to the Charm section in the Cyclopedia, click on the charm you want to apply (or not), and look where it says, select creature. It will only show you all the creatures you've already unlocked that you can apply the charm to. Alternatively, you can search for a specific creature if you don't want to browse the list.
The second option would be to go to the Cyclopedia and go to your Bestiary list to browse categories or use the search button, which isn't always the fastest.
Lastly, a reminder that you can track creatures using the Bestiary Tracker and you can also use fansites like Tibiopedia.PL to track your progress to share with your friends too.