Mods that are compatible with The Reunion:
(This is not a comprehensive list.)

Remako by CaptRobau https://captrobau.blogspot.com

-AI upscaled textures for fields, battle backgrounds, world map, movies, and character avatars.

SYW4 by Satsuki Yatoshi http://yatoshicom.free.fr/yforum/index.php

-AI upscaled textures for fields, battle backgrounds, battle effects, world map, movies, and mini-games.

NinoStyle Character Models by NinoStyle

-Custom character models. (Please note that Model Overhaul in Reunion must be turned off)

Avalanche Arisen by UpRisen https://www.nexusmods.com/finalfantasy7/mods/3

-Custom-made backgrounds for battles.

Symphonic Remasters: Redux by Symphonic Remasters and Unab0mb http://forums.qhimm.com/index.php?topic=20240

-Complete Final Fantasy 7 music track replacement.

Dual-Font UI by Orichalcon alternate link for X-Box 360 Buttons

-Complete UI replacement suited for play on bigger screens in high resolutions. Not compatible with SkyHawk's X-Box One Buttons mod.

X-Box One Buttons by SkyHawk

-Mod that keeps the original UI and font in-tact, but changes the PlayStation button icons to X-Box One button icons. Not compatible with Dual-Font UI.

Italian Translation by usb and Caledor

-R06g in Italian.

Cae Lumen's Class Challenge by Cae Lumen https://www.twitch.tv/mertiseile4178

-Mod that helps set the game up for a self-imposed class restriction for each character.