Simple mod that replaces every painting with art from Echo, replaces the Endermen with Socket Men, changes every song to an Echo song, and replaces a handful of sound effects. Everything but the Endermen texture was taken straight from the files in the game.

Note: None of the art is mine, and that includes the Socket Man. That was made by reddit user bksniperguy, whom I tried to reach out to but their account was unfortunately suspended. If anyone knows how I could properly reach out to them, let me know. If you're checking this mod out yourself, I both thank you for this wonderful texture and make it abundantly clear that I will take this down and upload a version without that texture if you so desire. Regardless, here's a link to the original post: www.reddit.com/r/FurryVisualNovels/comments/l6rx7k/a_texture_i_created_for_minecraft_the_replaces/

SFXs replaced
Cave ambience (partially)
Door being opened/closed (fully)
Endermen noises (fully)
Equipment breaking (fully)
Fall damage (fully)
Fishing (partially)
Page flip (fully)
Player being hit (fully)
Stepping over grass/gravel/cloth (fully)
Underwater ambience (partially)

Generic
Aerie > themeforalonelywolf
An ordinary day > when stars align
Ancestry > meeting2
Calm1 > goodmorning
Calm2 > mitt
Calm3 > neutral
Comforting_memories > bittersweet
Creative1 > bookofjob
Creative2 > jennastheme
Creative3 > lazy (unused in Echo)
Creative4 > sex (unused in Echo)
Creative5 > Vanishing_Paradise (used as main menu theme in old builds)
Creative6 > this lingering hope
Firebugs > sU
Floating_dream > bent
Hal1 > nicetomeetyou
Hal2 > nostalgia
Hal3 > quiet
Hal4 > reverb
Infinite amethyst > becauseforeverythingthereissomeone
Labyrinthine > acousticbreeze
Left to bloom > end ("end" from the actual files in Echo, not Minecraft! Obvious, but confusing)
Nuance1 > payton
Nuance2 > TJtheme
One more day > Epiphany
Piano1 > banter
Piano2 > intimate
Piano3 > loneliness
Stand tall > jennastheme
Wending > hitchhikers

Menu/Credits
Credits > wyawamv2
Menu1 > Theme
Menu2 > Theme
Menu3 > themepiano
Menu4 > themepiano

Music discs
5 > when_your_arms_were_around_me
11 > whispers
13 > blurry
Cat > bgfunkysexy
Blocks > rock
Chirp > amphitheater
Far > BGkitworth
Mall > Reckoning
Mellohi > backstage1
Otherside > moth
Pigstep > oldwinds
Stal > backstage2
Strad > backstage3
Wait > Wastelandp2
Ward > hiphop

Underwater
Axolotl > deadlybeauty
Dragon_fish > daze
Shuniji > melancholia

The End
Boss > argument
End > echothemedark

The Nether
Chrysopoeia > wasted
Nether1 > 748
Nether2 > cast_from_dust
Nether3 > themeforalonelywolf2
Nether4 > unease
Rubedo > brianstheme
So_below > blackballed

Note²: Minecraft loves playing its default main menu songs instead of the replacements about 50% of the time, for some reason. I'm not good enough to figure out why and much less how to fix that, but every song apart from the main menu ones should work consistently.

Simply extract the mod folder into C:\Users\[​YourUserHere]\AppData\Roaming\.minecraft\resourcepacks and turn it on by opening the game, then going into Options > Resource Packs. Should work even if you're told it's not for the appropriate version (compatible with 1.19, no guarantee for other versions).

If you don't like any of the sound effects, textures, or songs, I suggest navigating the mod's folder and deleting the files that you dislike. This mod has a few too many things for me to simply make an alternative download link.
Paintings are found under Echo > assets > minecraft > textures > painting
Socket man is found under Echo > assets > minecraft > textures > entity > enderman
Sound effects are found under Echo > assets > minecraft > sounds > every folder except "music" and "records"