These might be too low power, but I've seen some cubes run these cards that I find quite elegant:
They work well in artifacts and ramp, though the Lotus is card disadvantage, therefore it needs to be in a deck that can mitigate that disadvantage. If your cube has artifact destruction, be careful with them as you could get blown out by
Thrashing Brontodon! Sol Ring isn't very good if the colored mana requirements are too high, but it's probably the most playable.
Some fun combos/synergies:
-
Darksteel Citadel +
Sol Ring +
Frogmite - 2/2 on turn 1
-
Mox Ruby +
Shrapnel Blast - 5 damage to the face on turn 1, 66% better than a bolt
-
Mox Pearl +
Glint Hawk - free creature
- Mox +
Manifold Key - filter mana
-
Black Lotus +
Divination - free sorcery speed
Mental Note
-
Black Lotus +
Seasons Past - cast as early as turn 3 and get more value out of the cmc 0
-
Black Lotus +
Auriok Salvagers - infinite mana
-
Mox Sapphire +
Ensoul Artifact - turn 1 5/5! Probably too good, so don't run Ensoul.
Some issues are:
- These cards tend to be a bit expensive due to their scarcity, apart from Sol Ring.
- They don't come in foil, so they'll stand out like a sore thumb in a foil cube.
- They can lead to some crazy fast starts, like Mountain, Black Lotus, sac, Ravenous Giant.
Though in a lower power cube you wouldn't be running a 5/5 for 4.