I'm not really sure how to be. Pretty much any object in your home can be used as enrichment for a bunch of species, for example. Anything added to an animal's environment is enrichment.
Indeed, even something like a new log on a climbing structure qualifies. Even sounds and smells of the neighboring species can be, as well as other novel sounds and smells. (Worth noting some sounds and smells are stressors rather than enrichment)
For species trained as ambassadors, leaving their exhibits for a program or training session also often qualifies.
The long and short is basically anything qualifies as long as it's positive for the animal (particularly in the respects of it doesn't stress the animal and cannot forseeably hurt the animal).