What's New is Old Again is a resource pack that puts new, more recent textures (starting from ones added in 1.14, up to textures added in 1.17) and applies them to versions 1.11 through 1.12.2.

This resource pack is for anyone playing older versions of Minecraft, but those who also prefer the textures from newer versions.

What's New is Old Again has mod support!
In addition to modifying nearly every single Minecraft texture, this resource pack adds textures for the following mods (among others), which are just from my personal mod pack:

• Applied Energistics 2
  
• Draconic Evolution
• Compact Solars
• Davinci's Vessels
• Draconic Evolution
• Ender IO
• Ex Nihilo Creatio
• Extra Utilities 2
• Extreme Reactors
• Industrialcraft 2
• Immersive Engineering
• Industrial Foregoing
• Iron Chests
• Mob Grinding Utilities
• Morph Mod
• Mystical Agriculture
• Mystical Agradditions
• Tinker's Construct
• Thermal Foundation
  
• Tiny Progression
• Twilight Forest

I apologize if I didn't provide enough information in regards to the mod support, my knowledge is limited.

When will you finish this resource pack?
honestly? probably never.

Changelog
6/21/2021
Sprited a bunch more ingots for all new mods, along with a few minor touchups such as the mob grinding utils fan and some tiny progressions items.

6/24/2021
Sprited more thermal foundation items, updated minecraft water's color to more closely match new colors, and did some other touch ups and new sprites. I also deleted some redundant files to reduce overall file size.

August 2022
added the new villagers, horses, and zombie pigmen mob models. also added bed textures (i forgor 💀)

September 2022
added new sprites from the newer versions of AE2 and biomes o plenty