 Basilisk Sentinel | 1 | 1/104, 3 rolls |
 Berry (Awake) | 1 | 1/409.6 |
 Berserk barbarian spirit | 1 | 1/1,024 |
| Black demon (Regular) | 1 | 1/397.19 |
| Black demon (Wilderness Slayer Cave) | 1 | 1/229.62 |
| Black dragon (Regular) | 1 | 1/618.26 |
| Black dragon (Wilderness Slayer Cave) | 1 | 1/618.26 |
 Black Guard Berserker (Red) | 1 | 1/2,048 |
| Black Guard (Level 25) | 1 | 1/2,048 |
| Black Guard (Level 48) | 1 | 1/2,048 |
 Black Heather | 1 | 1/1,024 |
| Black Knight | 1 | 1/682.67 |
 Black Knight Titan | 1 | 1/682.67 |
 Blood Reaver (Ancient Prison) | 1 | 1/2,048 |
 Blood-starved venator | 1 | 1/2,096, 3 rolls |
 Bloodthirsty Hydra | 1 | 1/2,048, 9 rolls |
 Bloodveld (Normal) | 1 | 1/512 |
| Blue dragon | 1 | 1/409.6 |
| Blurite rocks | 1 | 8/32,768 |
 Body Golem (Golem) | 1 | 1/52 |
 Boris | 1 | 1/8,192 |
 Borrokar | 1 | 1/8,192 |
 Brambickle | 2–5 | 10/128 |
| Brimstone chest | 25–35 | 5/60 |
 Bronze dragon (Standard) | 1 | 1/492.75 |
 Brutal black dragon | 1 | 1/618.26 |
 Brutal blue dragon (Catacombs of Kourend) | 1 | 1/483.66 |
 Brutal green dragon | 1 | 1/829.57 |
 Brutal red dragon | 1 | 1/618.26 |
| Bryophyta (Free-to-play) | 1 | 1/512 |
| Bryophyta (Members) | 1 | 1/512 |
 Bull shark | 1 | 1/1,600 |
| Calcified rocks | 1 | 8/32,768 |
 Callisto | 50 | 4/126 |
 Calvar'ion (Normal) | 17 | 4/128 |
 Captain Bleemadge | 2–4 | 10/128 |
 Captain Daerkin | 2–5 | 10/128 |
| Captain Dalbur | 2–4 | 10/128 |
| Captain Klemfoodle | 2–4 | 10/128 |
 Captain Ninto | 2–5 | 10/128 |
| Casket | 1 | 8/128 |
| Casket (Reward pool) | 10–20 | 1/230 |
 Catablepon (Level 49) | 1 | 1/808 |
 Cave abomination | 1 | 1/409.6, 3 rolls |
 Cave bug (Level 6) | 1 | 1/409.6 |
| Cave crawler | 1 | 1/2,048 |
 Cave horror (Worker) | 1 | 1/409.6 |
 Cave kraken (Cave kraken) | 1 | 1/533.33 |