I have always felt the main part of the game is a tabletop skirmish game. That’s the roots of the hobby, right? So the first action I want to support is combat.
The basic system actions involved are: to hit, to defend, to damage, to resist. Tangentially, we also have movement, psychological tricks, and creating modifiers like cover and concealment. Movement and modifiers fall within the realm of defensive actions, but tricks can affect others, so I would classify them as both attack and defense. Blending “mental” and physical actions merits an article by itself but some crossover is important, and I think Savage Worlds provides an excellent example. My primary purpose is to apply the rule of tiers to assign combat skills.
With this in mind:
Attack skils: brawling, melee, shooting
Defense skills: dodge, parry
Damage skills: by weapon, weapon + attribute, attribute alone
Resist skills: by armor, armor + stamina, stamina alone
Movement skills: hide, run, climb, jump
Tricks: feint, provoke, dissuade