I just grab a packet of cat grass seeds because they're easy. I believe sometimes its oat, rye, or wheat grass. When I plant them myself, the grass lasts for a couple of weeks max...unless my cats decide they want some.

Then when its either devoured or wilts, I just plant more or have some already waiting.

Aside from cat grass and cat nip, I'm sure there are plants that aren't toxic for cats to eat, but I don't know if I would specifically select them for cats to munch on. I heard valerian and honeysuckle are like catnip but I don't know from experience.

For the price of a tub of ugly "cat grass," I bought a nice pot of "purple fountain grass" that looks very nice, will last until a freeze, and the cats (and dogs) enjoy very much. It's also full enough to hide a few chewed blades, and if I bring it in for the winter, it'll come back next spring.