UOR based PVP with additions to various skills to provide a wider range of templates that can compete.
In a nutshell:
Stun Mages: Wrestling + Anatomy allows Stun Punch attack
Theifs: Wrestling + Arms Lore allows Disarm attack
Evaluating intelligence >= 80 + Anatomy >= 80 accounts as wrestling (old OSI UOR based mechanic)
Alchemy gives bonuses for potion usage (effect strength and duration)
Tank Mages: All melee weapons have a nerfed version of the “insta hit”
Lumberjacking: Gives a bonus when using an axe
Bowcrafting: Gives a damage bonus when using a bow
Carpentry: Gives a damage bonus when using wooden non-ranged weapons.
Mining: Gives bonuses when using hammer picks and war axes
Peacemaking: Along with taking the victim out of war mode, it also disturbs magical spells
In PVP the UOR weapons special blows work (Crushing Blow, Paralizing Blow, Concussion Blow) while in PvM context, those moves are replaced by your
Skill Masteries perks.