Every Steam Workshop article tells you who grew the most. But raw subscriber totals hide the part that actually predicts a game's mod ecosystem health: who absorbs installs, how fast, and how broadly.
Using ModSignal's snapshot history across 7.34 million tracked Workshop mods and 396 games, we measured net new installs — the difference in total subscriptions between two snapshots exactly one week apart (September 13 → September 20, 2026) — for games with at least 200 comparable mods. The result is a living leaderboard of which game ecosystems absorbed the most demand in a single week.
And one game ran away with it.
Slay the Spire 2 absorbed more installs than anyone — from almost a standing start
| Game | Mods compared | New installs (7d) | % of mods gaining |
|---|---|---|---|
| Slay the Spire 2 | 1,640 | 627,964 | 84.6% |
| MECCHA CHAMELEON | 718 | 325,866 | 93.0% |
| Teardown | 1,981 | 287,301 | 67.6% |
| Palworld | 1,512 | 260,382 | 82.3% |
| Rivals of Aether | 3,908 | 258,626 | 92.8% |
| Your Only Move Is HUSTLE | 1,923 | 233,100 | 80.8% |
| Call of Duty: Black Ops III | 3,271 | 217,532 | 43.0% |
| Crusader Kings III | 1,989 | 177,031 | 60.4% |
| 鬼谷八荒 (Tale of Immortal) | 1,973 | 172,660 | 84.2% |
| Sid Meier's Civilization VI | 3,816 | 167,596 | 67.3% |
Slay the Spire 2 is the standout — and not because it's the biggest Workshop game by raw size. It's only weeks into its early-access Workshop, yet its mods absorbed 628,000 new installs in one week, and did it from just 1,640 comparable mods. That's an average of roughly 383 new installs per mod in a single week — a concentration that only genuine launch-phase ecosystems produce.
The launch wave is unmistakable. Of Slay the Spire 2's 629,227 net new installs, 181,481 (29%) came from mods published in the last 60 days — that's 686 fresh mods already pulling real installs. When a Workshop launches, the earliest foundation mods don't just ride the wave; they are the wave.
The foundation mods that eat a launch
Slay the Spire 2's week is dominated by a small set of structural mods that other mods depend on — the same pattern every healthy card-game Workshop shows:
| Mod | Game | New installs (7d) | Total installs |
|---|---|---|---|
| RitsuLib | Slay the Spire 2 | 31,840 | 618,617 |
| BaseLib | Slay the Spire 2 | 30,230 | 790,949 |
| ARAM: Mayhem | Slay the Spire 2 | 26,314 | 341,338 |
| UE4SS Experimental | Palworld | 21,434 | 1,447,190 |
| PalSchema | Palworld | 16,359 | 1,012,551 |
| ARAM: Mayhem: Extra Expansion | Slay the Spire 2 | 12,849 | 155,778 |
| Core Breach | Teardown | 11,462 | 31,231 |
| JmcModLib | Slay the Spire 2 | 10,445 | 213,362 |
| MSGK_Regent | Slay the Spire 2 | 10,149 | 249,735 |
Notice what's at the top: RitsuLib and BaseLib, the script-and-base libraries that hundreds of other STS2 mods depend on. On a new Workshop, install velocity concentrates in the infrastructure layer first, because every content mod that gets installed pulls its dependencies along with it. If you're a creator deciding where to build, the absorption leaderboard is telling you exactly where the foundation — and therefore the long-term install base — is being laid.
MECCHA CHAMELEON and the 93% gain rate no one talks about
The game with the healthiest week by another measure wasn't Slay the Spire 2 — it was MECCHA CHAMELEON. Its mods showed a remarkable 93.0% gain rate (668 of 718 compared mods added installs), second only to Rivals of Aether (92.8%). When 9 in 10 mods in an ecosystem gained installs in the same week, that's not a single-hit spike — that's a broad, healthy upgrade cycle.
Contrast that with Call of Duty: Black Ops III (43.0% gaining) or ARK: Survival Evolved (38.5%). Those ecosystems absorbed large absolute install totals, but only because a handful of huge, long-lived mods are still turning over — a minority of their mods are actually growing. Absolute installs tell you scale; gain rate tells you breadth. An ecosystem where 93% of mods rise is compounding, even if the headline numbers are smaller.
Reading the leaderboard as an absorption story
The naive way to read this data is "who has the most momentum." The more useful way is to think about absorption:
- Launch waves concentrate. New Workshhops (STS2) and relaunch cycles (MECCHA CHAMELEON) pull enormous install totals from a small number of recent foundation mods. The earliest structural mods capture outsized lifetime value.
- Breadth is the health signal. High gain rates (90%+) mean an ecosystem is broadly ascending; low gain rates behind big totals mean a few giants are propping up an otherwise flat scene.
- Fresh mods matter disproportionately early. In STS2, 686 mods younger than 60 days produced 29% of the week's installs. In a launch, the newest mods aren't marginal — they're the market.
For a studio deciding whether to open or expand a Workshop, or a creator deciding which ecosystem to build for, weekly install absorption is the honest leading indicator. Momentum articles tell you who's popular. This is who's becoming structurally important.
How we measure
All figures come from ModSignal's live snapshot history: we take the latest snapshot of each mod on September 20 and the most recent snapshot on September 13, and compute the exact difference in subscriptions. Games with fewer than 200 comparable mods (a snapshot pairing for both days) are excluded to avoid noise. This is a pure 7-day net install delta — not an estimate, not a projection.
Explore the live Steam Workshop demand graph to watch which ecosystems keep absorbing installs, or zoom into Slay the Spire 2 and Your Only Move Is HUSTLE directly.