Going back to Tristram and playing the game of Diablo 1 for the season. Remaster everything from D1 for the season and the full season is playing the story to D1 from normal, nightmare and hell difficults. The cosmetic for the season are the outfits from D1, the rogue, sorcerer and warrior 3 different outfits, plus different skins from the uniques weapons of D1 and D1 vases skins for items liek the focus and totem.
Sounds like you want to see D1 content in D4. If that’s the case, you want to post this in the D4 forums.