A one-mana artifact that taps for two colorless — printed in 1993, banned nowhere, and still the single most-played nonland card in every color of Commander.
Any ramp strategy. One mana for two colorless is the best rate in the format for pure acceleration, regardless of what the rest of the deck is doing.
Fast mana rock shells. It's the cheapest, most reliable enabler for any deck leaning on artifact mana — Basalt Monolith, Isochron Scepter combos included.
Precon and budget upgrades. It's one of the single highest-impact one-card upgrades available to almost any preconstructed deck straight out of the box.
How it does in Commander
As the commander
It's an artifact, never a commander — its entire job is sitting in the 99 and doing the same thing on turn one of every game, whoever is leading the deck.
In the 99
About as close to a universal include as Commander has: colorless, cheap, and good in a mono-white stax deck exactly as much as a five-color combo deck.
Formats it's strong in
Every color and archetype. There's no deck shape that doesn't benefit from doubling its mana on turn one, which is why it's the single most-played nonland card in the format.
Fast, high-power pods. A turn-one Sol Ring is often the difference between casting a key piece on curve or a turn late.
Formats it's weak in
Decks that specifically punish artifacts. Rare, but a deck built entirely around hating out artifacts has to weigh whether its own Sol Ring is worth the inconsistency.
Nowhere else, really. There's no honest weakness to list here beyond the rare hyper-specific anti-artifact build — that's the whole reason it's this ubiquitous.
Synergistic cards
Isochron Scepter — One of the cheap mana rocks that makes the Dramatic Reversal combo math work.
Basalt Monolith — Another artifact mana source that pairs with Sol Ring toward the same fast-mana curve.
Kobolds of Kher Keep — Nothing special — Sol Ring is good with literally anything that costs mana, which is the point.
Any turn-one play — Sol Ring's real synergy is with tempo itself: whatever your deck wants to do a turn early, it does it a turn earlier with this in the opener.
Is it worth the price?
Reprints across dozens of products have kept most Sol Ring printings inexpensive, with the price climbing only for premium foil or Secret Lair treatments. It's worth owning at least one of regardless of price point — this is the rare card that's simply correct in almost every deck.