The first of these non-class specific additions is -- brace yourself -- new hats. Eighteen new hats, to be precise, which presumably add two new hats to each of the game's nine classes' wardrobes. (Math'd!) The first map to be revealed is Arena Offblast, a tricky little battleground perched atop a shear mountain cliff. Players will need to stay wary of the cliff's edges, lest they plummet to their death, and stain their lovely new hats with gray matter.
Stay tuned to the TF2 blog -- they should be adding more information about the classless update in the coming days.