| Rust monster | 0.5 | Monstrosity | Medium | 14 | 27 | | unaligned | | Monster Manual (SRD) | 13 | 12 | 13 | 2 | 13 | 6 |
| Rutterkin | 2 | Fiend (demon) | Medium | 12 | 37 | | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Saber toothed tiger | 2 | Beast | Large | 12 | 52 | | unaligned | | Monster Manual (SRD) | 18 | 14 | 15 | 3 | 12 | 8 |
| Sahuagin | 0.5 | Humanoid (sahuagin) | Medium | 12 | 22 | swim | lawful evil | | Monster Manual (SRD) | 13 | 11 | 12 | 12 | 13 | 9 |
| Sahuagin baron | 5 | Humanoid (sahuagin) | Large | 16 | 76 | swim | lawful evil | | Monster Manual | | | | | | |
| Sahuagin priestess | 2 | Humanoid (sahuagin) | Medium | 12 | 33 | swim | lawful evil | | Monster Manual | | | | | | |
| Salamander | 5 | Elemental | Large | 15 | 90 | | neutral evil | | Monster Manual (SRD) | 18 | 14 | 15 | 11 | 10 | 12 |
| Satyr | 0.5 | Fey | Medium | 14 | 31 | | chaotic neutral | | Monster Manual (SRD) | 12 | 16 | 11 | 12 | 10 | 14 |
| Scarecrow | 1 | Construct | Medium | 11 | 36 | | chaotic evil | | Monster Manual | | | | | | |
| Scorpion | 0 | Beast | Tiny | 11 | 1 | | unaligned | | Monster Manual (SRD) | 2 | 11 | 8 | 1 | 8 | 2 |
| Scout | 0.5 | Humanoid (any race) | Medium | 13 | 16 | | any alignment | | Monster Manual (SRD) | 11 | 14 | 12 | 11 | 13 | 11 |
| Sea hag | 2 | Fey | Medium | 14 | 52 | swim | chaotic evil | | Monster Manual (SRD) | 16 | 13 | 16 | 12 | 12 | 13 |
| Sea horse | 0 | Beast | Tiny | 11 | 1 | swim | unaligned | | Monster Manual (SRD) | 1 | 12 | 8 | 1 | 10 | 2 |
| Sea spawn | 1 | Humanoid | Medium | 11 | 32 | swim | neutral evil | | Volo's Guide to Monsters | | | | | | |
| Shadow | 0.5 | Undead | Medium | 12 | 16 | | chaotic evil | | Monster Manual (SRD) | 6 | 14 | 13 | 6 | 10 | 8 |
| Shadow dancer | 7 | Humanoid (elf) | Medium | 15 | 71 | | neutral | | Mordenkainen's Tome of Foes | | | | | | |
| Shadow demon | 4 | Fiend (demon) | Medium | 13 | 66 | fly | chaotic evil | | Monster Manual (BR) | 1 | 17 | 12 | 14 | 13 | 14 |
| Shadow mastiff | 2 | Monstrosity | Medium | 12 | 33 | | neutral evil | | Volo's Guide to Monsters | | | | | | |
| Shambling mound | 5 | Plant | Large | 15 | 136 | swim | unaligned | | Monster Manual (SRD) | 18 | 8 | 16 | 5 | 10 | 5 |
| Shield guardian | 7 | Construct | Large | 17 | 142 | | unaligned | | Monster Manual (SRD) | 18 | 8 | 18 | 7 | 10 | 3 |
| Shoosuva | 8 | Fiend (demon) | Large | 14 | 110 | | chaotic evil | | Volo's Guide to Monsters | | | | | | |
| Shrieker | 0 | Plant | Medium | 5 | 13 | | unaligned | | Monster Manual (SRD) | 1 | 1 | 10 | 1 | 3 | 1 |
| Sibriex | 18 | Fiend (demon) | Huge | 19 | 150 | fly | chaotic evil | Legendary | Mordenkainen's Tome of Foes | 10 | 3 | 23 | 25 | 24 | 25 |
| Silver dragon wyrmling | 2 | Dragon | Medium | 17 | 45 | fly | lawful good | | Monster Manual (SRD) | 19 | 10 | 17 | 12 | 11 | 15 |
| Skeleton | 0.25 | Undead | Medium | 13 | 13 | | lawful evil | | Monster Manual (SRD) | 10 | 14 | 15 | 6 | 8 | 5 |