Creature tokens have been a part of Magic since just about the very beginning. However, since token permanents inherently have to be simple in gameplay to prevent memory issues, creatures are the only card type that can (realistically) have no abilities and still affect the game, and most of the evergreen keyword mechanics are for creatures only, noncreature tokens are a relatively recent innovation and not much has been seen of them. According to Mark Rosewater, though, we should be seeing more of them.
It’s definitely design space to explore.
Imperial Mask was a design that used noncreature tokens considerably before Gild did, and Mirrorworks was capable of making tokens that copied noncreature artifacts, but these were considered odd one-offs, and no one thought Imperial Mask's future would actually come to pass. But it appears concerns over the complexity issues in R&D have been dispelled; we may well see land tokens with basic land types in the future, or maybe even artifact tokens that enter the battlefield heralding something bigger which are small parts of a greater mechanized whole.