Not exactly a house rule but a definition ( as I understand them) of how card traits work:
Traits on Action Cards can be categories in to four groups: Rule, Career, Race, Effect
Rule Traits are the exceptions on an action card that overrides any basic rules concerning action cards. Most rule Traits are written on the card but others are defined in the rule books.
Basic (can be obtained for free at character creation)
Reaction (can be played when it’s not your turn)
Social (can be used in social combat)
Epic (requires player to be Rank3)
Support (action will benefit the Party)
Rank x (requires player rank to be equal or cost is more)
Ongoing (effect last for some time)
Flying (flying creature only)
Petty (spell casters can be obtain for free at character creation)
Enhance (modifier on an Action)
Twin Weapon (requires more than one Hand-weapon)
Pet (only a Pet can perform the action)
Mounted (have to be mounted to perform the action)
Teamwork (similar to support)
Drunken (Must be drunk/drugged to perform the action)
Thunder (Gunpowder weapon required)
Active Defense (can be used to counter another’s action that effect you)
Rally (no rule just a certain type of action)
Actions with a Career traits require some sort of formal training to obtain, some of them are easy to obtain others may be impossible to obtain if you are not in the right career. Players must get GM approval and may be required to buy the action as a non-career advancement.
Trollslayer, Diesto, Zweihander, Slayer, Ancestor, Way of the Sword, Ritual Dance, Bulwark, Noble, Criminal, Engineer, Hunters Eye, Judgement, Watcher, Saga, Duel of Wits,
Action with Race Traits indicate who can use the card, this is rough guideline when choosing cards for NPC and monsters. Players are unable to obtain any card with Race Traits.
Greenskin, Dark Elf, Skaven, Monstrous, Chaos, Dragon, NPC, Swarm
Action cards with Effect Traits indicate what effect the action has, what kind of damage they deal etc… These effects can be changed to suit the creature using it; fire can change to frost etc.