Some NPC's in the world are able to train you in certain skills.
Trainers
For 3 silver the NPC will train you to 30.0 skill points in the selected skill, it doesn't matter if you are at 0.0 skill points or 29.9 skill points. It'll always cost 3 silver.
You're not able to purchase training if you're above 30.0 skill points.
Not all NPC names are unique in each city, however their list of skills available for training can differ between cities.
Alchemy
Alchemists found in Alchemy Shops
Eldeir Village: Nicodemus the Alchemist
Valus: Pad
Oasis: Miiz
Black Forest Outpost: John
Animal Lore
Stable masters found at the stables.
Valus: Indiana
Animal Taming
Stable masters found at the stables.
Valus: Indiana
Archery
Woodsmiths found in carpenter shops.
Valus: Joshua
Guards in Black Forest Outpost.
Bashing
There's no trainers available for bashing. Use a training dummy to gain up to 30.0
Training dummies are available in Pyros Landing and Valus.
Beastmastery
There's no trainers available for Beastmastery.
You gain skill from having your pets attack something.
Blacksmithing
Metalsmiths found in Blacksmith shops.
Helm: Adam
Eldeir Village: Samogh
Pyros Landing: Justin (Metalsmith)
Oasis: Adam
Black Forest Outpost: Bruce
Blocking
Guards found throughout cities.
Fighters, these NPCs are not marked on the ingame map.
Brawling
Guards found throughout cities.
The herbalist in Valus.
Valus: Gerald
Certain Traders found at General Stores.
Valus: Paul
Carpentry
Woodsmiths found in carpenter shops.
Valus: Joshua
Channeling
Mages, these NPCs are not marked on the ingame map.
Cooking
Innkeepers & Chefs
Eldeir Village: Michael, Dr. Paws
Black Forest Outpost: Elliot
Evocation
Mages, these NPCs are not marked on the ingame map.
Fabrication
Fabricators found in Tailor shops
Eldeir Village: Robert the Tailor
Black Forest Outpost: Ross
Fishing
Fishers found at docks or beaches.
Pyros Landing: Justin (Fisher), Tidus
Healing
Traders found at General Stores.
Eldeir Village: Guy the Trader
Black Forest Outpost: Guy the Trader
Heavy Armor
Guards found throughout cities.
Fighters, these NPCs are not marked on the ingame map.
Hiding
Rogues, these NPCs are not marked on the ingame map.
Inscription
Scribes at Scribe Shops
Lancing
There's no trainers avaliable for lancing. Use a training dummy to gain upto 30.0
Training dummies are avaliable in Pyros Landing and Valus.
Light Armor
Fabricators found in Tailor shops
Black Forest Outpost: Ross
Rogues, these NPCs are not marked on the ingame map.
Lockpicking
Rogues, these NPCs are not marked on the ingame map.
Lumberjack
Woodsmiths found in carpenter shops.
Valus: Joshua
Magic Affinity
Mages, these NPCs are not marked on the ingame map.
Manifestation
Mages, these NPCs are not marked on the ingame map.
Mining
Metalsmiths found in Blacksmith shops.
Helm: Adam
Eldeir Village: Samogh
Pyros Landing: Justin (Metalsmith)
Oasis: Adam
Black Forest Outpost: Bruce
Piercing
The rogue in Black Forest Outpost and Pyros Landing, this npc is not marked on the ingame map.
Slashing
Fighters, these NPCs are not marked on the ingame map.
Stealth
Rogues, these NPCs are not marked on the ingame map.
Treasure Hunting
There's no trainers avaliable for treasure hunting.
Because of this it's highly recommended to choose treasure hunting as a starting skill for a treasure hunter build.
Vigor
Guards found throughout cities.
Fighters, these NPCs are not marked on the ingame map.