Mods that are better than the base game -

[Rand /pol/]

Kaiserreich and Old World Blues are far better than the base HOI4 game and DUST has its moments compared to vanilla Fallout NV.

 

[IN 041]

GregTech for Minecraft.

 

[Jeanne d'Arc]

I've heard Long War for the modern XCOM and XCOM 2 are absolute essentials if you're into masochistic gaming experiences.

I liked the base games enough. Maybe when I retire and can afford to sink that much time into shit I'll probably fuck up horribly 70-80 hours in, but I'll take everyone else's word for it.

 

[PL 001]

Median XL Sigma for Diablo 2. Really revitalized my interest in an almost 20 year old game. These guys did their work.

 

[HeyYou]

Europa Barbarorum for Rome 1 and then Divide et Impera for Rome 2. Vanilla Rome 2's improved a lot, though. Pretty much any mod for Vicky 2, as well.

More controversially, I think Black Mesa has evolved to be more fun to play than Half Life 1. It is extremely hard to go back after the new Xen levels.

 

[Teri-Teri]

Command and Conquer: Rise of the Reds and Command and Conquer: Shockwave.

 

[ScrapBuyer]

does garry's mod count?

 

[HeyYou]

does garry's mod count?

It's pretty much entirely different from Half Life 2, so it's really more its own thing. It's like calling Counter-Strike a mod.

 

[Slowpoke Sonic]

tf2 mario kart map mod

 

[ScrapBuyer]

It's pretty much entirely different from Half Life 2, so it's really more its own thing. It's like calling Counter-Strike a mod.

yeah that's fair

 

[Basil II]

like any Bethesda game. MC, Paradox games.

 

[Really makes you thunk]

I think Enderal is an objectively better game than vanilla Skyrim, even if the latter has way more content (but it's a mod vs a AAA game, so that can be excused, and quality > quantity anyway, right?)
I admittedly haven't played Nehrim, but I assume it's in the same boat, but with Oblivion.

 

[Dick Justice]

Jagged Alliance 2 1.13
Counter-Life
Give Me Deus Ex
Q3 CPMA
LURK
7,62 Hard Life
Darkest Hour
Fallout: Wanderer's Edition
SMOD Tactical
Heroes Unleashed
Raven Shield 2.0
SEFmod
FO2 Restoration Project
Cold As Hell
I could do this all day, OP

 

[Maskull]

Even in its early state I would argue that Tamriel Rebuilt is the definitive Morrowind experience.

 

[Friend computer]

Even though i loved the base game Europe in ruins for Company of heroes 1, got me playing a couple of months extra, together with my mates, though it started to become pretty elitist in the end that i was involved with it, and certain people were blacklisted and clicks had formed which pretty much only played together, which didn't help the small community to grow, and new users to join.

 

[Marco Fucko]

Movie Battles is a multiplayer mod for Jedi Academy that not only adds maps and characters from all movies + popular EU content but also refines the saber combat away from something you had to learn glitches for to something resembling a directionally sensitive dueling system.

Still active even after all these years:

 

[Gravityqueen4life]

pokemon rom hacks. my favorite being sacred gold. makes a decent pokemon game into one of the most fun games i have played.

 

[dunbrine47]

Open Rollercoaster Tycoon 2 with the most important feature being the ablity to fast forward.

 

[Takodachi]

"Dark World Fantasy" for Crusader Kings 2 and the Gamindustri mod for Civ5

 

[Easterling]

"Perisno" for mount and blade warband, It's one of the biggest and most well made mods I ever played for that game.