Do you like to play Vanilla or Modded?

Well, it's all vanilla for me, at first. I like to play the game as it is intended to be played.

After I have beaten the game, I might mod it to replay it. However, due to more games having achievements - I like to get those. So no modding still, even if I do replay :D

Although, if some games have no achievements and I am replaying them - graphical mods mostly! :) Or some quest mods or QoL mods. (Morrowind, I am looking at you)

I prefer strawberry.

Usually vanilla first and if i really like the game i try to download some mods that don't break the lore in any way like more lore friendly weapons and armor for skyrim etc...
I also love mount and blade warband mods so far i have played over 10 total conversion mods and most of the mount and blade warband mods are really well made (gekokujo,anno domini 1257,warsword conquest,etc...)

I prefer vanilla, but I did get a mod for Skyrim because it included bug fixes, I think.

Generally vanilla. For some particular games, I can use mods to fix the horrible UI and/or improve the graphics. And by "particular" I typically mean anything around Bethesda 👀👀

Depend of the game, for Torchlight II full play it on vanilla.
For Sonic Generation, first finish the vanilla game, than i have modded it for new levels, like the Unleashed Project Mod
For Heroes of Hammerwatch, quickly go into mod because the vanilla game is too hard and too much grind for me.
And for Distance and Ballistic NG, quickly go into mod because the base game only represent a quarter of what of the games have really to offer (and the base game have a solid content)
For Ballstic NG : Enai Track Pack (add +80 awesomes tracks to the game)
For Distance : Pines of Chaos Levels (All his mains tracks are really good track, as good as official tracks)

I have too many games wanna play so i prefer vanilla and go for another one after beating previous game.

Very much depends on the game.
Most games I only play vanilla, and have no interest in mods.
Other games for example, are just too frustrating to play without mods.
For example, I played Fallout 4 on release, and had mods installed almost from day 1.

Other games you want to replay, and the mods make it more enjoyable.
For example Civilization games, or Half Life: Alyx give you a whole new experience re-playing the game with mods.

Vanilla first, modding is an option later. But for most games there is no "later" because of the backlog. Others that I keep playing struggle with mods rarely being up to date with the latest patch etc.
So I'd say at most 2% of my playtime are with modded games. And usually only some UI improvements or similar.

Mostly I prefer to play without mods. In some MMORPG (EQ2 for example) I like to use some mods changing the interface to a more convenient for me.

In a few complex strategy games (Slitherine's "Eagle Day to Bombing the Reich" for example) I edit data files myself mostly to simplify them a bit and to make unit and production management easier by removing excessive almost the same weapon types or conglomerate small units into larger formations, but doing so I do try to preserve the original strength balance.

Rarely there are games like Stardew Valley, that after playing for a bit I feel, that I would enjoy more with some changes, that mods can make. In case of Stardew Valley I've decided to play without day length constrains (time freeze), because I just don't like doing things in a rush. There are also some games in which mods practically replace expensive DLCs (surprisingly not banned by devs even on Steam Workshop), that I don't own, and those at times I use.

Somewhere between first and second. I generally play it vanilla a bit to see the original, then I mod halfway through.

Modded of course. Because it's fun GTA:SA. And because Skyrim and Skyrim, and again Skyrim, and again, and again, and again...

Generally I like to play everything as intended, without mods. A few exceptions can be made when fanmade mods fix glitches, controls, resolution and the like (like the FAR mod with Nier;Automata).
Later, or for a second playtrough, I may VERY rarely mod the games. I only really did it with Skyrim in my third playtrough to spice things up a bit. Not to mention how Enderal is technically still a mod, despite practically providing a new game's experience.
The last I used a mod was in A Hat in Time, because the creator encouraged the modding community from the start and mods can be easily enabled in-game. Most of them are extra maps and cute outfits, and the majority does not deviate so much that it would feel out of place.

I always prefer Vanilla except if the game is a mess and a grafical fix is needed or a fix with the controls. I won't change the character skin and play as a suimsuit Jill in RE3 for example.

Vanilla player here, I'm not savvy enough to fiddle with mods. I've only been able to add some really really basic "copypaste this file into the game directory" mods for Bethesda games.

Vanilla and most of time modded after

Really depends on the game. I play most vanilla, but for example Minecraft i only play modded, vanilla is just too boring.

I only use mods if they include fixes to in-game failures that developers neglected to address. Some games are very unbalanced or need a cosmetic upgrade, for instance. Of course, often what you need is a patch, not a mod when it comes to other issues like compatibility and bugs.

I think you must be really into a game to play it over and over again adding small or cosmetic changes (or even big ones). Even when I really liked a game, I prefer to play a different one. Most of us own 100s, if not 1000s of games and there are plenty good ones to discover in your backlog.

Vanilla first. After i completed the game or got to the point where i got bored i start Modded. I usually used mod that either change a lot of gameplay, add more stuff without change the base, or visual mod.
Game i like to mod: Mount and Blade: Warband; Darkest dungeon.

I gladly take any UI improvements I can get, which is especially true for Bethesda games. Gameplay is something I want to keep vanilla tho because I want to play the game the way the devs designed them, even if mods would greatly improve upon that. At the end of the day I want to be able to say that I have played/beaten a certain game but with gameplay mods installed, no matter how minor the changes are, it feels like I played a different game.

in Sekiro Shadow Die Twice,Cyberpunk2077 and the first AssassinsCreed i like to apply the nvidia freestyle details filter,it make the game looks so much better sort of enhanced or remastered version,but free.
i have also personal videos that show how much wonderful extreme is the difference night to day,i can't share it here because violate SG rules but if you wan see it you can add m in steam.
In Cyberpunk and Sekiro i can see details in the arms,clotches etx. thatwith normal\vanilla can't see , and in ac too but about the buildings,colums etc

Usually vanilla, with the odd exceptions of Civilization 4 and original Doom engine level sets.

I usually prefer to at least try the game in its vanilla state before modding. Most games I will do a full run on vanilla, but occasionally there are games where mods improve them so much that I'll dive in pretty early (Skyrim, Stellaris, XCOM2, and Kenshi are a few examples).

As for the type of mods I play with, it is basically whatever looks interesting to me. Usually a mix of cosmetic, QoL, and new content. I'm also a sucker for expanding random name lists - if a game generates anything with random names (characters, npcs, mission names, etc), I will mod those right off the bat (and usually will do it myself, rather than use someone else's name mod).