Witcher 3 bestiary is a journal tab where a creature is logged after you kill it, follow tracks, or read a book. Each entry shows a model, lore, and icons for oil, bombs, and signs. Below you find the categories from the English game version and links to individual monster pages.
How the in-game bestiary works
You open it in the menu next to quests and the map. An entry fills in after a kill, witcher-sense tracks, or a book from a merchant. For each type you see what to coat on your sword and which signs or bombs make sense. The silver sword is for monsters, the steel sword for people and animals. In settings you can turn on automatic oil use.
The game splits creatures into eleven categories. The same group shares one oil and fights in a similar way. Below that come Humans, who are missing from the in-game journal but show up all over the map, and humanoid oil works on them the same way. Some monsters also have a named variant, for example a royal wyvern or the dragon from Fyresdal, who is actually a venomous forktail.
Draconids
Draconid oil on your silver sword can boost attack against this group. While they circle in the air you knock them down with Aard when they are close enough, or with your crossbow. On the ground you fight with the sword or signs. Golden oriole can help against poison from tail and claws on some types.
Elementals
They guard ruins, mines, and laboratories. One hit can take a lot of health. Your silver sword wants oil against magical beings. A dimeritium bomb breaks the magic holding them together, and Quen hides the first heavy hit before you can dodge.
Insectoids
In caves, pits, and swamps they climb at you in packs and often bring poison. Your silver sword wants insectoid oil. Igni burns a nest or egg sac, or more hatch from the cocoon. Golden oriole helps when a bite poisons you.
Hybrids
Your first real fight in the game is the royal griffin. You hunt it in White Orchard with Vesemir. Your silver sword wants hybrid oil. While they fly you drop them with the crossbow, on the ground you fight with sword and signs.
Necrophages
At graveyards and battlefields a pack surrounds you. You cut down one quickly, and smarter ones are led by alghouls. Your silver sword wants necrophage oil. Against graveirs, Black Blood and Yrden help. On foglets you use moon dust before they turn immaterial.
Cursed Ones
A werewolf heals and grows stronger at full moon. You meet a berserker on Skellige in The King’s Gambit. Your silver sword wants cursed oil. Moon dust stops healing, and on archespores Aard interrupts the leap from the ground.
Specters
In a fight they turn immaterial and your sword misses until they stand in Yrden. Your silver sword wants specter oil. Moon dust helps when they try to vanish. You meet barghests only in Blood and Wine in Toussaint.
Relicts
Each of them fights differently. What they share is relict oil on the silver sword. A leshen calls wolves and crows, and Igni plus a dimeritium bomb work best on it. A fiend can stun you with its third eye, and Samum plus Devil’s Puffball help there.
Vampires
Lower ones like fleders live on blood, regenerate, and can vanish. Higher vampires live among people and your medallion will not vibrate near them. Your silver sword wants vampire oil. Black Blood before the fight helps when they drink from you. Moon dust keeps them visible and Yrden slows them in range.
Ogroids
Nekkers pour out of holes in packs, and a cyclops swings slowly but hard. Your silver sword wants ogroid oil. Quen hides the first hit and Axii stops a cyclops for a moment. You can sometimes get past a troll with a riddle.
Beasts
In Velen wolves jump you by the road when you rush to a quest. They always come at you in a pack. Your steel sword wants beast oil. The Beauclair beast from Blood and Wine is the exception until you learn it is Dettlaff.
Humans
There are plenty of them on the map in roadside camps and in cities. Hanged Man’s Venom on your steel sword boosts attack against them. Elves and dwarves count for the same oil. Shields often block Aard and Igni, so you deal with archers before swordsmen up close.
Summary
On a specific creature you find oil, weaknesses, and where you run into it. The big picture of the game is in the Witcher 3 review. More guides sit on the Witcher 3 hub.