| Star spawn hulk | 10 | Aberration | Large | 16 | 136 | | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Star spawn grue | 0.25 | Aberration | Small | 11 | 17 | | neutral evil | | Mordenkainen's Tome of Foes | | | | | | |
| Spy | 1 | Humanoid (any race) | Medium | 12 | 27 | | any alignment | | Monster Manual (SRD) | 10 | 15 | 10 | 12 | 14 | 16 |
| Sprite | 0.25 | Fey | Tiny | 15 | 2 | fly | neutral good | | Monster Manual (SRD) | 3 | 18 | 10 | 14 | 13 | 11 |
| Spring eladrin | 10 | Fey (elf) | Medium | 19 | 127 | | chaotic neutral | | Mordenkainen's Tome of Foes | | | | | | |
| Spirit troll | 11 | Giant | Large | 17 | 97 | | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Spirit naga | 8 | Monstrosity | Large | 15 | 75 | | chaotic evil | | Monster Manual (SRD) | 18 | 17 | 14 | 16 | 15 | 16 |
| Spined devil | 2 | Fiend (devil) | Small | 13 | 22 | fly | lawful evil | | Monster Manual | | | | | | |
| Spider | 0 | Beast | Tiny | 12 | 1 | | unaligned | | Monster Manual (SRD) | 2 | 14 | 8 | 1 | 10 | 2 |
| Spellcaster mage lvl 6 | 0 | Humanoid (any race) | Medium | 12 | 31 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster mage lvl 5 | 0 | Humanoid (any race) | Medium | 12 | 27 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster mage lvl 4 | 0 | Humanoid (any race) | Medium | 12 | 22 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster mage lvl 3 | 0 | Humanoid (any race) | Medium | 12 | 18 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster mage lvl 2 | 0 | Humanoid (any race) | Medium | 12 | 13 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster mage lvl 1 | 0 | Humanoid (any race) | Medium | 12 | 9 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster healer lvl 6 | 0 | Humanoid (any race) | Medium | 12 | 31 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster healer lvl 5 | 0 | Humanoid (any race) | Medium | 12 | 27 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster healer lvl 4 | 0 | Humanoid (any race) | Medium | 12 | 22 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster healer lvl 3 | 0 | Humanoid (any race) | Medium | 12 | 18 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster healer lvl 2 | 0 | Humanoid (any race) | Medium | 12 | 13 | | any alignment | | Essentials Kit | | | | | | |
| Spellcaster healer lvl 1 | 0 | Humanoid (any race) | Medium | 12 | 9 | | any alignment | | Essentials Kit | | | | | | |
| Specter | 1 | Undead | Medium | 12 | 22 | fly | chaotic evil | | Monster Manual (SRD) | 1 | 14 | 11 | 10 | 10 | 11 |
| Spectator | 3 | Aberration | Medium | 14 | 39 | fly | lawful neutral | | Monster Manual | 8 | 14 | 14 | 13 | 14 | 11 |
| Spawn of kyuss | 5 | Undead | Medium | 10 | 76 | | chaotic evil | | Volo's Guide to Monsters | | | | | | |
| Soul monger | 11 | Humanoid (elf) | Medium | 15 | 123 | | neutral | | Mordenkainen's Tome of Foes | | | | | | |