This amazing list (previously called  "Probably the Best Free Security List in the World") compiled by Editor AKO contains thousands of links to free security-related Windows desktop applications and web applications, with the goal of listing everything available that's not malicious or of low usefulness. Everything is neatly sorted into categories so it's easy to navigate.

AKO notes "This list does not give recommendations (except for the My Choices page), but it contains links to other Gizmo's Freeware pages that give recommendations."

That said, do also check out AKO's My Choices page as his personal choices are impeccable.Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.