Remains

Remains are items dropped by creatures upon their death. They are dropped 100 percent of the time, and include both monsters and players. The type of remains dropped by a creature depends upon the physical characteristics of the creature.

Creatures with bone remains
Many living and undead creatures drop bones of different kinds, such as regular Bones, Big bones, and Dragon bones. Creatures that drop bones include mammals (such as Humans), birds (such as Chickens), reptiles (such as Snakes), and amphibians (such as Frogs).

Most humanoid giants drop big bones, even if they might be considered in other categories of creatures. For example, many fire-based creatures drop ashes, but Fire giants drop big bones.

Creatures derived from those dropping bones commonly drop bones as well. These include Zombies, Undead chickens, Undead cows, Crawling Hands, Skeletal hands, and Zombie hands. Other creatures in this category have altered remains or no remains at all. For example, many ghostly creatures, including ghosts and Revenants, do not have any remains and the Shades of Mort'ton have remains named specifically after them.

Semi-humanoid Scabarites drop bones, even though their insect-like appearance suggests an exoskeleton rather than an internal skeleton.

Giant Rock Crabs drop bones, even though other exoskeleton-based creatures do not, including regular Rock crabs.

Ankous, as a cross between ghosts and skeletons, drop bones, unlike most ghostly creatures which have no remains.

Various creatures drop bones that are characteristic of that creature:
 * Jogres drop Jogre bones.
 * Monkeys drop Monkey bones.
 * Monkey Guards drop Monkey bones (large).
 * Zombie monkeys drop Monkey bones (Zombie).
 * Wolves drop Wolf bones on members' worlds. (On free worlds, they drop ordinary bones, even if killed by members.)
 * Bats, Albino Bats, and Giant bats drop Bat bones.
 * Zogres and Skogres drop Zogre bones.
 * The Shaikahan drops Shaikahan bones.
 * Adult Chromatic dragons and Metal dragons drop Dragon bones.
 * Baby chromatic dragons drop Baby dragon bones.
 * Ourgs drop Ourg bones. (Although few ourgs can be found at present, General Graardor is an ourg, and Slash Bash might be an undead ourg.)
 * Skeletal Wyverns drop Wyvern bones.
 * Dagannoth Rex, Dagannoth Prime, Dagannoth Supreme and Dagannoth Sentinels drop Dagannoth bones. (Other Dagannoth drop ordinary bones.)
 * For some reason, all creatures in the Lumbridge catacombs drop bones, even if they are creatures without skeletons such as Warped flies or warped cockroaches.
 * Airut drop Airut bones.
 * Adamant dragons drop Adamant dragon bones.
 * Rune dragons and Elite rune dragons drop Rune dragon bones.

Creatures with other remains

 * Vampyres drop Vampyre dust.
 * Vyrewatch, Vyrelords and Vyreladies all drop Vyre corpses.
 * Shade creatures drop remains. Loar shades drop Loar remains, Asyn shades drop Asyn remains, and so on for Phrin shades, Fiyr shades, and Riyl shades.
 * Metal dragons drop several bars of their metal, in addition to dropping dragon bones.
 * Aviansies drop Feathers in addition to bones.
 * Baby tanglefeet drop Leaves.
 * Almost all snails, such as Myre blamish snails or Giant Snails, always drop shells. However, the Ravenous snail, which was released when Slayer Challenges were released, does not.
 * Jungle spiders drop Spider carcasses, as noted above.
 * Living rock creatures drop Living rock remains. However, these must be mined to be obtained.
 * Swamp Snakes encountered in the Temple Trekking/Burgh de Rott minigame usually drop 'dead swamp snakes' as remains, from which players can obtain swamp snake hides. If the player's follower in the activity becomes involved in combat with a swamp snake, the snake may drop regular bones instead, even if the player kills the snake.
 * Monkey on the island of Karamja drop Monkey corpses during and after the quest Tai Bwo Wannai Trio instead of Monkey bones.

Trivia

 * An Oyster is an item you obtain from fishing, not a creature you can fight. You can, however, end up with an Empty oyster from it, which could be considered to be a form of remains.
 * Bloodvelds are demons by definition of Slayer Masters (and are confirmed as such because of their weakness to Silverlight and Darklight), but they drop bones, not ashes.
 * During the Rum Deal quest only, a Fever Spider will drop a Fever spider body, an ingredient used in making Captain Braindeath's 'rum'. Also during this quest, the player will fight an Evil Spirit, which drops ashes despite seeming to be a ghostly creature.
 * As mentioned above, Giant Rock Crabs drop bones, even though other exoskeleton-based creatures do not, including regular Rock crabs. This might be a mistake by Jagex, or there may be some unknown, physical or magical reason for their having bones.
 * Some creatures occasionally drop multiple bones, like bloodvelds which occasionally can drop several bones and big bones, even though they always at least just drop one set of bones. In these cases, it can be regarded that the creature was 'carrying' the extra bones, just like the other, non-bone items it may drop when killed.
 * Fayrgs and Raurgs presumably dropped Fayrg bones and Raurg bones, as these bones can be found in Ogre coffins at Jiggig. Neither creature has been seen in recent ages and are generally believed to be extinct followers of Bandos.