The simipliest form of discover is to just get all the db idents and do a string filter on them. I'm not sure it gets better then that. The get-schema function alid linked seems to have some hints in it.

in Datomic, attribute definitions are themselves entities

you can query them normally:

:find ?attribute
[_ :db/ident ?attribute]

and you can also augment them with your own information

that datomic doesn't know about

so you can add attributes like :drewverlee.attribute/relates-to

to relate one attribute to another

or to assist making schema html documentation