just out of curiosity...for those claiming pc had the best exclusives, can we get some examples. it's ok to include small indies, which i love but preferably some big budget examples of why PC has the best exclusvies? I mean, I own a PC and I love it. I'd say elite: dangerous is probably my favorite exclusive PC game but...that's coming to consoles so...any other big examples? Prison architect is another favorite but I'm struggling to think of anything else that really rocked my world this year. undertale was good. maybe game of the year material. what else? I don't really think it's fair to include early access games here either. also, games that have released on ios and android shouldn't count either. Im just feeling people say 'PC, obviously' without even trying to give examples of recent top tier exclusives.
Oh boy, it's hard because there's so many. In this year alone, for example, there were literally about 25-50 games releasing every week on Steam alone, and this number is absolutely no exaggeration. And the surprising thing is a high number of them were actually really good.
I am a horror enthusiast, so I'll focus on that, but this year there were multiple really good titles for every taste and genre. I'm sure someone else will answer more generally, but there's a HIGH number of games that releases on PC.
On Steam alone, there are 326 games that have releases this year so far with the horror tag. This includes basically every horror game on consoles, and most come out months before their console counterparts and with better all around versions, but a high number of other titles.
For comparison quickly, checking, there were (So far, as December is not done yet)
2,784 games that have released on Steam alone this year. And this is straight-up games, not including DLC or other things. A lot of those titles were exclusive to PC, and a surprising number of them were actually really good.
For my horror enthusiasm, a few I want to point out from this year that didn't show up on other platforms:
Here's just a few misc horror games, one genre alone, and some exclusive games definitely worth checking out that came out this year:

Sunless Sea
You are the captain of a ship off to sea. A unique horror rogue-like with Lovecraftian tones where you can do anything to survive, eat your crew, discover secrets of the deep, all told with amazing writing and a unique narrative.
Screens:

Into The Gloom
Simplistic style, but featuring an extremely tense atmosphere, effective scares, and twisted puzzles. Into the Gloom also has a branching storyline and is up there as one of the scarier games I've played despite its simplistic style.
Screens:

Lakeview Cabin Trilogy
An episodic horror-comedy game where you can do whatever you want, mess around with random items in the environment, survive a killer, become the killer, kill you friends, streak naked, summon the devil, get eaten by wildlife, kill yourself, ride a motorcycle, a zipline, jump into a wood chipper, play different group of friends, etc. It's basically an open-world sandbox stylized like horror movie sequels, currently 5 out of 6 of the episodes are released, very fun, dumb, funny, and sometimes tense.
Screens:

DreadOut
Indonasian horror game inspired by Fatal Frame, quite good, low-budget, but makes up for it in design and ambition. Second half of the game released this year, included some unforgettable horror scenes. One of the best modern 'classic' styled horror games to release.
Screens:

The Music Machine
A stylistic narrative-driven experience about a girl who either has split personalities or is possessed by the spirit of an adult killer who travel back to a campsite she once stayed at now long abandoned to learn a hidden truth. Quite interesting, I liked it quite a bit.
Screens:
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Kholat
Atmospheric game based on the Devils Pass incident in Russia, go through an open would mountain range where strange occurences occur. Includes vocal tracks by Mary Elizabeth of Silent Hill fame and voice acting by Sean Bean. Some pretty interesting moments and gorgeous visuals.
Screens:

Sylvio
Very unique horror game starring a psychic woman going to talk with ghosts in an abandoned amusement park surrounded by mystery. Use audio recordings you pick up to record and decipher ghost messages by editing them, drive around, survive ghosts, solve puzzles. Has won some recognition, including one of Rock, Paper, Shotgun's top 25 horror games of all time, and is incredibly unique.
Screens:

Homesick
You explore an abandoned building overrun with plant life and decay, trying to figure out clues to what happened to lead to this place to become abandoned for your own personal reasons, but soon get trapped into a nightmare. Gorgeous visuals, clever puzzles, interesting scenes.
Screens:

Monstrum
Randomly generated horror rogue-like where you get a random ship layout, but also a random monster of several. You have to find an escape method of the ship, there's several ways to accomplish this, while you avoid a sinister monster on-board the ship with you, all with different behaviors. Can be very different from experience to experience based on layout, the monster chasing you, and which method (of multiple possible) you're trying to use to get off the ship.
Screens:

Her Story
By the creators of Silent Hill: Shattered Memories, an FMV game where you put together the story of a woman through tapes and records you have that unveils a very interestingly woven tale.
Screens:

Spooky's House of Jump Scares
A freeware horror game where you must transverse 1000 rooms to escape a mansion full of strange designs and monstrosities. Somewhat of a parody game, but definitely has its moments.
Screens:

Fran Bow
Drawn horror point'n'click featuring a young girl locked into a mental institute after the murder of her parents she blames on a demon she saw. She believes if she can escape the nuthouse, her old cat will lead her to the saftey of her aunt's home, so she goes to make her way out. Interesting world, characters, puzzles, and up there as one of the best horror point'n'clicks I've played.
Screens:

Stray Cat Crossing
A grim dark fairytale-like story of a strange colorful surreal but dark and twisted world with strange characters, and a story that slowly unveils. Includes animated cutscenes and a 16-bit style.
Screens:

Layers of Fear
One of the best regarded horror games of this year, Layers of Fear tells a story of an artist delving into a twisted world of his own nightmares and paintings. Somewhat P.T. inspired, but very much its own thing, many consider it to have passed its source of inspiration and be one of the best horror experiences of the year.
Screens:

Undertale
More of an RPG, but it does sport the horror tag on Steam as well. One of the best regarded games of this year that has become one of the highest rated and highly acclaimed games of all time, and for good reason.
Screens:
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AND I AM SO HOLDING MYSELF BACK. There's a bajillion other horror exclusives that released, some of which is very, very good. Including Pathologic HD Remaster, the re-translation and new artwork version of Higurashi, a game I really liked called The Coma... And it goes on and on, and this is just horror games I'm naming, there's almost 3000 games that released on Steam alone this year, and many are very, very good.