WItcher 3 decoctions do not have numbers on them. Nothing does. But someone looked into the game files and posted it in the CD Projekt Red forums. And here they are, extra spacing for ease of reading.

Witcher 3 decoction numbers

Katakan Decoction - Increases Critical Hit Chance by 5%.

Arachas Decoction - 20% damage reduction bonus while at zero weight, 0% bonus while at full weight.

Cockatrice Decoction - All alchemy creations can be used one additional time (except Decoctions)

Archgriffin Decoction - Consumes 100% Stamina for 5% Enemy HP Reduction using a Strong Attack.
Also counts the damage the Strong Attack makes in the total (the damage total on screen does not
show the 5%, but only the strong attack damage).

Water Hag Decoction - Damage dealt is increased by 50% when character HP is at its maximum.

Nightwraith Decoction - Geralt's maximum HP is increased by 50 with each foe killed. Effects
lasts until meditation or fast travel.

Ekimmara Decoction - Damage dealt to foes regenerates HP. (Health restored = 10% of damage dealt + 1)

Chort Decoction - +40% to knockdown resistance for each 100 points of carry weight. (This got
updated in 1.12, so needs to be checked again)

Foglet Decoction - Increases Sign Intensity during Cloudy Weather by 25%.

Wyvern Decoction - Each blow landed increases Attack Power by 1% until fight ends or damage
is taken. (No max limit)

Doppler Decoction - Increase critical hit damage by 50% when attacking from behind.

Troll Decoction - Regenerates Vitality during (20) and outside (100) of combat.

Noonwraith Decoction - Sets Blindness, Hypnotized, Knockdown/Stagger/Confusion, Slowdown effects
duration to 0.5 sec.

Succubus Decoction - Attack power grows in 1% increments every 2 sec over the course of the fight
until reaching a maximum of threshold of 30%.

Alghoul Decoction - Adrenaline Points are generated 50% more quickly until the player receives damage.

Fiend Decoction - Increases the amount of weight the Witcher can carry by 20.

Forktail Decoction - 50% to attack power and spell power after at least three of these actions: counter,
attack, sign, bomb, crossbow. Clears buff after the attack, removed at the end of combat.

Grave Hag Decoction - Each foe slain accelerates Vitality regeneration by 5 for the duration
of the battle (No Max Limit)

Wraith Decoction - When a single hit reduces HP by 30% or more, a Quen shield is triggered.

Earth Elemental Decoction - Increases resistance to vitality depleting critical effects (burning,
poison, bleeding) applied during combat by 10%. 

Ekhidna Decoction - Performing actions that consume Stamina regenerates Vitality
(100% Stamina Use = 10% HP restore)

Ancient Leshen Decoction - Each Sign cast increases Stamina regen by 2/s until the remainder
of the fight (No max limit)

Basilisk Decoction - Applies a random beneficial effect at dusk and dawn. The effect lasts 6 hours. 

Werewolf Decoction - Running, sprinting and jumping outside combat does not consume Stamina.

Nekker Warrior Decoction - Mounts never Panic. 50% increase to mounted combat damage.

Leshen Decoction - A portion of the damage dealt by enemies is reflected back on the
attacker. (2% of damage taken + 10) 

Griffin Decoction - Taking damage increases damage resistance (slashing, piercing, bludgeoning,
rending, elemental) in 1% increments up to a maximum of 25% for the remainder of the fight.

Reliever's Decoction - Increases damage dealt by 10% and decreases damage taken by 15% against
Wraiths (slashing, piercing, bludgeoning, rending, elemental).


Source: this forum post https://goo.gl/HG6RL1 (shortened because of length. Original link in
past revisions of this gist)