Hack Name: Pokemon Yellow - Gen. II Graphics Patch
Hack of: Pokemon Yellow

You guys have waited a long time for this, but here it is!
I finally remade my Gen II Graphics Hack for Pokemon Yellow!

Summary of Features:
-Pokémon and trainer sprites taken from GSC
-A few trainer sprites devamped from FRLG that did not exist in GSC
-Updated all Pokémon palettes, and added individual trainer class palettes, to match GSC
-Pokemon back-sprites are now 48x48 and not zoomed in and pixelated
-Many graphics updated to match GSC, such as battle HUD, font, and text box border
-The Pokeball tile is always red (instead of goofy colors) in battles, in the Pokedex, and in the PC
-The "Pokemon owned" Pokeball tile in wild battles, from GSC
-Fully functional in-battle experience bar, from GSC

v1.1 Update: The EXP bar is now blue while playing in GBC mode!
(Note that when playing in SGB mode, the exp bar will still share the color of your health bar.)

Disassembly Repository:
https://github.com/dannye/pokeyellow-gen-II

Videos:
Gen II Graphics Patch: Exp Bar: https://www.youtube.com/watch?v=K8N4b0dk0mA
Gen II Graphics Patch: "Already Owned" Pokeball Tile: https://www.youtube.com/watch?v=DCANDefWruw
(Note that these are videos of my Red hack, but it works the same in this Yellow hack.)

I wouldn't make this hack for the Japanese versions unless a disassembly of Jap Red, Blue or Yellow was made.
And I don't imagine any of us making one soon.

sources:
https://www.pokecommunity.com/showthread.php?t=372328
https://hax.iimarckus.org/post/44418/