| Secret Plans (20 variants) | 385 |
| Sedge Sliver (20 variants) | 187 |
| Sengir Nosferatu (20 variants) | 136 |
| Serra Avenger (20 variants) | 41 |
| Shade of Trokair (20 variants) | 42 |
| Shaper Parasite (20 variants) | 85 |
| Shivan Meteor (20 variants) | 188 |
| Shivan Sand-Mage (20 variants) | 189 |
| Shriekmaw (20 variants) | 331 |
| Sidewinder Sliver (20 variants) | 43 |
| Sigil of the Empty Throne (20 variants) | 301 |
| Silence (20 variants) | 302 |
| Simian Spirit Guide (20 variants) | 190 |
| Sinew Sliver (20 variants) | 44 |
| Skirk Shaman (20 variants) | 191 |
| Skittering Monstrosity (20 variants) | 137 |
| Slaughter Pact (20 variants) | 138 |
| Slimefoot, the Stowaway (20 variants) | 386 |
| Slipstream Serpent (20 variants) | 86 |
| Sliver Legion (20 variants) | 261 |
| Sliversmith (20 variants) | 273 |
| Smallpox (20 variants) | 139 |
| Snapback (20 variants) | 87 |
| Solemn Simulacrum (20 variants) | 400 |
| Sorcerous Spyglass (20 variants) | 401 |
| Spell Burst (20 variants) | 88 |
| Spiketail Drakeling (20 variants) | 89 |
| Spinneret Sliver (20 variants) | 230 |
| Sporesower Thallid (20 variants) | 231 |
| Sporoloth Ancient (20 variants) | 232 |
| Sram, Senior Edificer (20 variants) | 303 |
| Stingscourger (20 variants) | 192 |
| Stinkweed Imp (20 variants) | 332 |
| Stonecloaker (20 variants) | 45 |
| Stonehorn Dignitary (20 variants) | 304 |
| Storm Entity (20 variants) | 193 |
| Stormcloud Djinn (20 variants) | 90 |
| Stormfront Riders (20 variants) | 46 |
| Strangling Soot (20 variants) | 140 |
| Street Wraith (20 variants) | 141 |
| Strength in Numbers (20 variants) | 233 |
| Stronghold Rats (20 variants) | 142 |
| Stuffy Doll (20 variants) | 274 |
| Sudden Death (20 variants) | 143 |
| Sudden Shock (20 variants) | 194 |
| Sudden Spoiling (20 variants) | 144 |
| Sulfur Elemental (20 variants) | 195 |
| Summoner's Pact (20 variants) | 234 |
| Sunlance (20 variants) | 47 |
| Swarmyard (20 variants) | 284 |