My drafters love Urza's Saga and so far it has played out extremely well in cube for us. I'm probably going to go up to three copies because I think it makes for a very lightweight way to incorporate artifact synergies into basically any deck.
My cube has a fairly large colorless section and a lot of it serves as a sort of utility backbone that most decks can leverage. There are just a lot of versatile and powerful options that are tempting to pick up during the draft because you'll usually play them however the rest of the draft goes. Some examples (chosen to exemplify widely playable utility cards, not all necessarily fetchable by Saga):
Of course, these ideas have been extensively discussed at riptide by many people. And you see variations across many power-levels:
With sufficiently high incidental artifact density with all of these flexible playables (maybe combined with stuff like e.g. Tireless Tracker
, Saheeli, Sublime Artificer
, Sram's Experstise
) decks that are not artifact-tribal per se can add a card like Marionette Master for free. You can choose to leverage the sub-theme or not during the draft without trainwrecking or being on-rails.
Three copies of Urza's Saga is really simple high power-level implementation of the same concept. It turns out that a lot of the widely playable utility artifacts and artifact creatures happen to have mana cost 0 or 1. Then just as in the Marionette Master example, basically any deck can adopt an artifact theme with extremely low cost. You're already happy to snag Saga targets during the draft. Then Saga combines these into a tutorable toolbox. And in turn, Saga makes tokens that reward you for having more random artifacts around. I especially like how light-weight this feels. You absolutely do not need to pivot to drafting all artifacts and a Saga package slots into an enormous number of game plans. It merely adds an extra dimension to certain cards both during drafting and during game play.
Some more narrowly-defined archetypes already play well with this style of subtheme. In Wildfire (for me it would be Balance) for instance, you'll likely play a very high density of artifacts even though you don't have any cards that key off artifacts explicitly. Those rocks give you extra mana that you can sink into Urza's Saga and power up your karnstructs.
And on top of this, you may or may not also include various artifact themes, whatever those may look like. Say, Welder, Urza, and KCI decks. In a different type of cube it might a Court Homonculus or Hardened Scales artifact aggro shell. These decks will happily play Saga but as a drafter, you don't need to be in a dedicated "archetype" for Saga to be relevant. So for me, triple Urza's Saga is an easy include to test out. I already run triple Wasteland
and plenty of enchantment removal to interact, and maybe Magus of the Moon, Spreading Seas and stuff like that become relevant. It'll be a fun thing to try.