it would be a cosmetic case so probably Meta cosmetics like spycrabs or something thats a pun about concjumping as tfc medic

In my op it would contain taunts, action items, unusualifiers etc. Something like not cosmetic or weapon.

Might sound like much but, what if has all the most popular cosmetics, items, taunts from each past crate/case, and even weapons too, but applied with a special "anniversary" tag to it, akin to "genuine" or other tags with its own unique text colouring to boot.

Ofc realistically speaking it could also just be a new specific cosmetic line made to celebrate TF2's history or just random cosmetics that have no real tie to the anniversary itself.