Stuck for Ideas? Here's some I prepared earlier:
Texture Packs:
No Optifine!
I wanted the pack to be accessible in vanilla Minecraft instead of requiring Optifine
Developer Art
Texture pack must look like it was made before 1.14 Texture Update
Old Music
Music by Daniel Rosenfeld is highly recommended
Mob Skins:
Old Feelings
Mob skins must meet the old feeling of Minecraft
Promised Texture or Concept Art
Mob skins must look like when they were promised or in concept art
Standard Resolution
Mob skin must be in default resolution
Mods:
Vanilla Style
Mods must look like a vanilla feature
Maps:
Old Building Style
Maps must be build in simple ways. Maps inspired by Bedrock Mushups is also allowed
Data Packs:
Developer Style Codes
Data pack codes must look like it was made by a developer. But it must also function as well
Blogs:
Showcases
Blogs must only be showcases of old Minecraft. A lore in blog form is also allowed