The Skyship Weatherlight and Predator, perhaps the two most prominent (and, as far as I know, the only) vehicles in the multiverse were implemented without such a mechanic (see: Skyship Weatherlight and Predator, Flagship , respectively)
Last week, the most recently (and controversially) banned cards Dockside Extortionist, Jeweled Lotus, and Mana Crypt blew up in price, showing that some fans clearly hope Wizards of the Coast will overturn the final decision of the now-disbanded RC
[Card]The Great Henge[/Card] serves the first role while being an artifact itself so that Emry gives us more reliable access to it, and [Card]Ensoul Artifact[/Card] does the latter while enabling Henge itself
Sagas set to expire concurrently are excellent targets for a spell like this
The free side of the mastery track will spit out the occasional booster, too
Flying, first strike, vigilance, trample, lifelink Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink