I recommend you limit yourself to one or two personal crests each. Most choose one each and occasionally a couple or individual will order one animal crest each with the sun or the moon in between them. Sometimes they will be represented as a diamond or other gemstones. Your freedom of choice.

You can combine two or more animal crests but 4 is maximum which limits the space for body parts, especially for a ladies smaller ring size, 2-3 max. The creatures can be flipped opposite of each other, or in the same direction. Your choice too.