It's important to keep cards that will help you add gas to your tank, so try to hold onto cards like Lucky, Pongo, Tinker Bell, Strike a Good Match, Hypnotize, and Improvize when you see them
The longer and more technical answer is that Hiram had phenomenal, borderline broken, synergy with Pawpsicle and Fortisphere , two inexpensive item cards that cost just 1 ink each and also allow you to draw a card when they're played
The original Dominaria had 97 historic cards to untap it
Christian has countless years of gaming and tech journalism experience under his belt, and can usually be found in his office 3D printing or staring at Pokmon cards.
Any permanent that has a good ETB effect is fair game
It's trivially easy to get it into your graveyard: that puts an Artifact into the graveyard, handy for turning on a Dragon Rage Channeller's Delirium ability or pumping up a 'Goyf, and providing another card