Gandalf the White, for example, is designed to mainly care about legends, but he can also break the famous artifact Isochron Scepter, as noted in this Reddit thread where users recognized the potential that Gandalf's ability adds to the Isochron Scepter
After going over all of the over 150 Legendary Creatures in Final Fantasy Magic: The Gathering , I'm relieved to say that there are a few less legendary options in Edge of Eternities
Like kicker and cycling, its a deciduous mechanic: Magic designers use it when needed , and its not necessarily in every set, or a set's main mechanic
As for the best of the new creatures, O'aka, Traveling Merchant turns your excess counters into carddraw, and Maester Seymour grows creatures of your choice as you grow him