The Gaming Den

So "D&D came out in 70's" is well known, but I'd like to get down when specific game mechanics or gameplay ideas got printed. There's a ton of pre-D&D board game stuff like "Hit points and AC came from a battleships game",
but when exactly were those?

Conan Unchained by David Cook, 1984, that was the first 'reserve hp' 'non magical healing' for D&D right? But did some other RPG do that before D&D?
Non-mechanical milestones, themes can count.

When did Gygax start running dungeon challenges at conventions and handing out official "use this at any D&D table" magic item cards?

Stuff I've gathered online...

1975 En Garde, GM-less game
1975 Tunnels & Trolls- first spell-point system
1977 Traveller, first skill instead of class based game
1984 Marvel Superheroes, first narrative-point meta currency game?
1984 Conan Unchained, first non magic fast healing and reserve HP mechanics in D&D at least
1985 Oriental Adventures: Kiai is the first non-magical resource for warriors in D&D I think
1985 Mekton, first mecha focused RPG, though board games preceed it
1986 Ghost Busters first dice pool RPG, though I don't know exactly how
1987 Ars Magica formalizes rotating GM's "troupe play"
1991 Vampire the Masquerade focuses heavily on LARP and less dungeon problem solving, milestone in marketing?
1991 Amber Diceless RPG, though it was played in the 80's before publishing
2000 D&D3e OGL system dominates the 3rd party market

I'm looking for more mechanics firsts, like when exactly berserk/rage, stances and stuff entered D&D or if other RPG's did it first.

Something along these lines seems very difficult if you're looking for an academic level of accuracy, in part because the concepts and ideas were discussed and distributed unofficially before they were published. The Strategic Review and later Dragon magazines included a lot of variant rules, and I think you'll find may of the 'firsts' released in the pages of the magazine first.

Why?

Hit Points were inspired by Fletcher Pratt's Naval War Game - the game uses Hull Points. It was published in 1940.

I know the Avalon Hill Games were popular with the early D&D players, so a lot of the things that ended up in D&D may have appeared there in one way or another.