I usually think QOL mods for games tend to be the best just because its purpose are to just make the experience better overall, but outside of that:

• There’s 2 mods for The Binding of Isaac I cannot play without: External Item Descriptions (so important it’s feature was added to the game, but it is still inferior to the mod) and ReactionAPI (seeing your character POG for good items and dance for incredible items is integral to the gameplay).
• Seamless coop on Elden Ring is also incredible and a must for playing with someone else.
• I haven’t finished it but the Archthrones mod for Dark Souls 3 was pretty cool.
• Ultrawide mods that work on Linux
• Skyrim mods that enhances the combat, skill tree and the ones that are genuinely impressive like adding transition animations

Generations Arena for Q3A was a good time, playing as any of the characters from previous id games and their different play styles

There was also a simple Akimbo mod for Q3a that allowed you to equip 2 guns and once

Requiem overhaul for Skyrim was my jam, makes it more immersive and touches just about everything in the game, from animals only dropping pelts / claws etc to trolls having hyper regeneration unless you use some kind of fire to negate it. Draugr are virtually immune to anything but silver weapons and fire. The damage is all turned up by magnitudes for both the player and npcs, so getting hit by a couple arrows can down you, a two handed axe will potentially one shot you in light armor. Would usually have to run around killing bandits for a while just to survive the starter dungeon.

Between Empires for Mount and Blade Warband.

It’s a total overhaul mod that switches the setting out to Europe and most of their colonies during the late 19th century, adds a bunch of new systems for politics and industrialisation, adds a tech tree, and some RTS elements for greater control of troop formations during battles.

Anything that Kaze Emanuar does is the best mod to ever exist. He made Super Mario: Ocarina of Time and is making/made his own whole refactored (like remastered the game engine) mod of SM64.

But then there’s a simple one that remove Gleba from Factorio that made my friend laugh so I like it.

Then Minecraft, Terraria, and Slay the Spire have absolute cinema for mods but I haven’t explored

Long war of the chosen for xcom, God I sank an embarrassing number of hours into the game just because of that mod.

I’ve been enjoying most Vintage Story mods, especially Expanded Foods/Cullinary Artillery. Though the amount of AI and vibe coding tolerated amongst VS mods is annoying with no required disclosures, so the game crashes semi often with all the mods I use now. There’s also no complete mod overhaul of the game because it’s sorta young and I’m pretty sure it originally started as a mod for minecraft in the first place (never played modded MC so idk).

Also been wanting to try Turyle WoW for a while, but haven’t started yet

The mod for Skyrim that turns all the dragons into Macho Man Randy Savage

JK+ for Jedi Academy! I spent probably more time playing that mod on multiplayer servers than any other video game when I was a teenager. Jedi Academy had a ton of great mods too, great single player campaigns, great multiplayer maps and skins, just an absolutely perfect modding scene.

Now while that’s my most played mod, I think my favorite mod is Movie Battles 2. MB2 is basically a hero shooter but without predatory monetization - you pick your classes each class has different skills so you can pick a different load out there’s some modes that recreate scenes from the movies some modes that are like free-flowing where you get a single life, and it has by far the best depiction of lightsaber combat in any Star Wars game, and it manages to do that without making the Jedi super OP.

Project M and P+ for Brawl

Desert Combat for Battlefield 1942

• Dark Future for Cyberpunk 2077

• Basically every mod made for Kerbal Space Program 1 (i loved that c. 2016 modding community so much i was like the resident cheerleader/beta tester/booster for the modders everyone was so sweet and nerdy)

• Kaiserreich for HOI4 even though i’ve evolved beyond it actually helped me conceptualize a leftist revolution, finally see leftists as good guys, and forced me to deep dive into so much 20th history of the left

• shoutout to the Star Trek Stellaris mod even if it ran like shit

• some fallout 4 mod that let me aesthetically build the Minutemen into an primitive anarcho-communist faction. i almost built a mod for that game to give it an actual story

• so many others mods to me are like fanfic is to my partner it’s my special interest but i am too sleepy/high to remember any others because if I did there would be like 100 entries.

Fortress defense for DF2014.

It added new hostile civs and was a very different experience where you couldn’t reliably export anything due to being under constant attack.

original tekkit and aether mod. The real og’s of minecraft modding, they hit a high so good Ive only ever been let down ever since. Dont forget to delete you META-INF folder!

If we are going for packs, then the original Feed the Beast map + modpack where you need to advance through the mods on a floating island and feed items to the beast contraption for rewards.

Individual mods red power 2. So much of that mod actually ended up in vanilla in some form. But it’s still not close.

Do hacks count? If so mother 3 English translation

https://www.nexusmods.com/skyrimspecialedition/mods/11802

Basically, you get a museum to put all your shit in. It rapidly becomes the focus of every playthrough I do.