I've been keeping a saga cube since Neon Dynasty for threads like these

For me personally, it's not necessarily about finding sagas that work well together, but finding effects that leverage the saga card type and its inherent characteristics to help my game plan. There's a wide power gap between the best sagas and the worst sagas, which means I usually default to drafting sagas on power level, and then figuring out my other cards based on these axes:
1. Cards that care about historic. (
Sarah Jane Smith,
Sentinel of the Pearl Trident,
Cabal Paladin,
Gloin, Dwarf Emissary,
Jamie McCrimmon). Also dovetails into artifact and legendary support.
2. Cards that care about enchantments (
Archon of Sun's Grace,
Doomwake Giant,
Eidolon of Blossoms)
3. Cards that care about sacrifice (
Obsessive Pursuit,
Goblin Blast-Runner)
4. Cards that care about things leaving play (revolt, void, disappear etc)
5. Cards that care about things going or staying the graveyard (
Starfield Mystic,
Fear of Missing Out,
Moonshadow,
Kami of Transience)
6. Cards that care about counters (
Scholar of New Horizons,
Storm of Forms,
Drown in Ichor,
Akki Ember-Keeper,
Signature Slam)
7. Cards that reset permanents (
Sunpearl Kirin,
Displacer Kitten,
Stickytongue Sentinel)
Putting my deck together involves figuring out how to exploit as many of these angles as possible and combining them to execute my game plan.
In the future, I also expect more possibilities to emerge based around exploiting saga triggers, along the lines of
Weaver of Harmony,
Gogo, Master of Mimicry and
Peter Parker's Camera. For that same reason, I think
Loki, God of Mischief has a lot of potential due to many sagas targeting permanents for multiple turns. This could be interesting design space if we got more cards like
Green Slime and
Trigger Happy.
Most of the Neon Dynasty transform sagas and Final Fantasy creature sagas +
Huatli, Poet of Unity are A++ in my book. Enchantment creatures as well, to a lesser extent, since they help with points 2 and 4-5 (enchantments entering/leaving and enchantments dying/being in the yard). I think the transform sagas from Avatar are mostly just okay and the praetor sagas from March of the Machine are pretty silly. The wedge sagas from Dragonstorm are nice to have with enough fixing, but they don't do much that guild sagas don't already do for a better cost. The Eldraine and LotR sagas +
City of Death opened up incidental trinket support by creating a bunch of artifact tokens to play with. It really gets that
Tough Cookie cooking.
I won't bore you with a rundown of how every set's sagas ranked for me, but Spider-Man and Marvel Super Heroes both got some excellent sagas and Spider-Man's at least were re-themed to be more Magic, so I hope MSH and Star Trek (yay more sagas!) get the same treatment eventually.
Flickerwisp is often mentioned, so here's a couple Saga-adjacent cards that are generic enough to pass as normal cube cards:

Two of my favorite decks to draft in this cube revolve around
The Antiquities War and
Brilliant Restoration. Antiquities War requires me to juggle enough artifact card type and trinket generators to get that big attack turn, while Brilliant Restoration asks me to juggle enough looting/sac and ramp to make sure I get there.