There's sure a few companies that would wish they could have control over those or see them erased from the face of earth (Activision-Blizzard having the rights to any new modded games made in Warcraft 3 Reforged in their TOS, Take-Two Interactive trying to take down big GTA mods, Nintendo bullying Youtubers playing BOTW with mods), but there's always a way for people to get their cake and eat it 😎
I find it really cool when people manage to crack open an otherwise completely closed off game to do their thing (decompilations like SM64 and OOT that eventually add modding features, UMVC3 getting a "clone engines" to add more characters than ever intended, every Smash Bros project that also manage to add more fighters, Sonic games and ports having bugfixes and improvements made by fans, and so on), which is a topic I would like to get more in-depth with someday, but there's also something magical about games that give you mod tools and people manage to run far beyond what they are supposed to do, like making a Toyota AE86 mod for TBOI (which is the only way I have beat that game lmao), the Doom community going crazy with both mods that push the original engine (like a mod based off Doom 2016) and mods that take advantage of modernized engines (like another mod based off Doom 2016, only even more accurate...and that's not even talking about GZDoom-powered games), and not just Garry's Mod as a whole starting as a sandbox experiment using the Source engine frmo Half-Life 2, but also whatever you can now find inside GMod itself.
The variety of stand-out weapons from different games and maps for different modes that exist are something taken for granted in this style of game but really it is quite cool from the players at the community that make these in first place. What other game you could say you could spawn a Lamborghini as Luigi and swing with Spiderman's webs while running away from Senator Armstrong in the backrooms?
...uhhh, yeah, maybe that one's a story for another day. But TTT is definitely and old community game mode that does thrive off the variety of content made for the game, which is great.
Guess I'll have to think about writing a proper post about this topic now that I see I've written this much for a reply 😅
Thank you for your comment! 😃