| Salamander | 5 | Elemental | Large | 15 | 90 | | neutral evil | | Monster Manual (SRD) | 18 | 14 | 15 | 11 | 10 | 12 |
| Sahuagin priestess | 2 | Humanoid (sahuagin) | Medium | 12 | 33 | swim | lawful evil | | Monster Manual | | | | | | |
| Sahuagin baron | 5 | Humanoid (sahuagin) | Large | 16 | 76 | swim | lawful evil | | Monster Manual | | | | | | |
| Sahuagin | 0.5 | Humanoid (sahuagin) | Medium | 12 | 22 | swim | lawful evil | | Monster Manual (SRD) | 13 | 11 | 12 | 12 | 13 | 9 |
| Saber toothed tiger | 2 | Beast | Large | 12 | 52 | | unaligned | | Monster Manual (SRD) | 18 | 14 | 15 | 3 | 12 | 8 |
| Rutterkin | 2 | Fiend (demon) | Medium | 12 | 37 | | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Rust monster | 0.5 | Monstrosity | Medium | 14 | 27 | | unaligned | | Monster Manual (SRD) | 13 | 12 | 13 | 2 | 13 | 6 |
| Rug of smothering | 2 | Construct | Large | 12 | 33 | | unaligned | | Monster Manual (SRD) | 17 | 14 | 10 | 1 | 3 | 1 |
| Rot troll | 9 | Giant | Large | 16 | 138 | | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Roper | 5 | Monstrosity | Large | 20 | 93 | | neutral evil | | Monster Manual (SRD) | 18 | 8 | 17 | 7 | 16 | 6 |
| Roc | 11 | Monstrosity | Gargantuan | 15 | 248 | fly | unaligned | | Monster Manual (SRD) | 28 | 10 | 20 | 3 | 10 | 9 |
| Riding horse | 0.25 | Beast | Large | 10 | 13 | | unaligned | | Monster Manual (SRD) | 16 | 10 | 12 | 2 | 11 | 7 |
| Rhinoceros | 2 | Beast | Large | 11 | 45 | | unaligned | | Monster Manual (SRD) | 21 | 8 | 15 | 2 | 12 | 6 |
| Revenant | 5 | Undead | Medium | 13 | 136 | | neutral | | Monster Manual (BR) | 18 | 14 | 18 | 13 | 16 | 18 |
| Retriever | 14 | Construct | Large | 19 | 210 | | lawful evil | | Mordenkainen's Tome of Foes | | | | | | |
| Remorhaz | 11 | Monstrosity | Huge | 17 | 195 | | unaligned | | Monster Manual (SRD) | 24 | 13 | 21 | 4 | 10 | 5 |
| Reef shark | 0.5 | Beast | Medium | 12 | 22 | swim | unaligned | | Monster Manual (SRD) | 14 | 13 | 13 | 1 | 10 | 4 |
| Reef manta ray | 0.5 | Beast | Large | 12 | 16 | swim | unaligned | | Extra (AideDD) | 13 | 12 | 12 | 1 | 12 | 4 |
| Redcap | 3 | Fey | Small | 13 | 45 | | chaotic evil | | Volo's Guide to Monsters | | | | | | |
| Red slaad | 5 | Aberration | Large | 14 | 93 | | chaotic neutral | | Monster Manual | | | | | | |
| Red dragon wyrmling | 4 | Dragon | Medium | 17 | 75 | fly | chaotic evil | | Monster Manual (SRD) | 19 | 10 | 17 | 12 | 11 | 15 |
| Red abishai | 19 | Fiend (devil) | Medium | 22 | 255 | fly | lawful evil | | Mordenkainen's Tome of Foes | | | | | | |
| Reaper of bhaal | 2 | Humanoid (human) | Medium | 15 | 27 | | chaotic evil | | Adventures (Descent into Avernus) | | | | | | |
| Raven | 0 | Beast | Tiny | 12 | 1 | fly | unaligned | | Monster Manual (SRD) | 2 | 14 | 8 | 2 | 12 | 6 |
| Rat | 0 | Beast | Tiny | 10 | 1 | | unaligned | | Monster Manual (SRD) | 2 | 11 | 9 | 2 | 10 | 4 |