Orphan Kitten with Stuffed Animal
There is a ton of enrichment options that are available to animal shelters since animal sheltering has evolved significantly since its infancy. I usually recommend cat toys for caged cats, vertical space, hiding spots, and socialization. You can read my entire guide on shelter cage enrichment by clicking here if you are interested in learning about enrichment strategies.
The single best enrichment option that I recommend for shelters is that they give each orphan kitten a stuffed animal to sleep with. Orphan kittens that come in through animal control or are surrendered may become stressed out or scared if they do not feel like they have companionship. The stuffed toys can also double as a pillow for kittens who may need additional warmth.
Stuffed animals can be rotated out every so often to remain novelty. I recommend that both toys and stuffed animals are rotated out every week. Catnip can be sprinkled on the toy and Feliway spray can be added as well.
Kittens or cat immune to catnip will benefit from fish oil rather than catnip. I prefer using stuffed animals that are about the same size if not just a bit bigger than the kitten so they can nest on it if they desire. I recommend cohousing kittens when possible to avoid the stress or lack of companionship that they can experience. All kittens or cats housed together should be vaccinated, dewormed, and checked over for any medical issues.
My top recommendation for shelters that take in orphan kittens is to avoid the shelter completely until they are healthy and vaccinated. This can be done by fostering the kitten right after they are processed into the shelter system to avoid being exposed to any disease causing pathogens. Maintaining a database of willing participants might be the best way to give orphan kittens what they really need.