Planescape Vortex of Madness. New Weird and fighting against anomalies.

I found some inspiration but I need more sources.

Do you remember the creepypastes? And the analogic horror subgenre? Or the backrooms, Fundation SCP or the monsters from the videogame "Scarlet Nexus" (or "Evil Within"). Or the kami war from Kamigawa (Magic the Gathering?).

My idea is the adventurers (style Planescape) arrive to a place like the plane of the mirrors, but they are things they can't understand, like in the videogames "Once Human", "Control" or "FBC: Firebreak". I don't mean something like the Lovecraftian horrors from the "Far Realm" but "monster anomalies created by a glitch in the Matrix" or astral constructs created by a divine power what is becoming mad. I think about surreal creatures that are more "elementals" than constructs or biological beings.

My intention is to add gem dragons what use their psionic powers like "damage control", trying to stop or delaye this surreal reality-wrapping.

What sources do you advice? Any monster or special place from creepypasta fiction?

Are you looking for things that are essentially a 'signal degradation' of reality? Things that seem like they're twisted off the real world and warped (glitched)?

I have a few versions of that in my game, but the one that is closest to the idea you seem to be referencing, to me, violates one of your premises because it has a tie to the Far Realms...

This is how I use the Shadowfell, Feywild and Ethereal Planes. These worlds are reflections of the Prime that are infused with the plane to which they connect. They mirror the Prime and have a tendency to shift to more resemble the current state of the Prime, although the presence of powerful beings can halt this shift and otherwise influence areas (such as creating Ravenloft domains in the Shadowfell). The Shadowfell is a mirror of the Prime that Connects to the Negative Energy Plane and everything in it 'tends' towards reflecting a dark and sickly version of the Prime - much like the Upside Down in Stranger Things. The Feywild is infused with Positive Energy from the Positive Energy Plane and is filled with saturated and infused reflections of the Prime that are addictive in how good it feels to be there - which is why the Fey living there seem so chaotic and addled. The Ethereal, for my games, is a transitive plane between the Prime and the Far Realms and is infused with insanity, madness and chaos.

I populate the Ethereal with the souls of madmen, aberrations, slaadi, geam dragons, psionic creatures (including sects of gith and illithid) and a homebrew version of sentient constructs modeled after the Cenobites from the Hellraiser series. The realm itself is a permanently mist shrouded reflection of the Prime that is always just a bit wrong. Though I've never used the term, calling it glitched makes a lot of sense. For example, it might look like a pitcher of water is floating in the air next to a table ... but as you approach it the pitcher seems to slide onto the table. A cat might open its mouth to meow, but the sound is delayed a second. In combat a PC might find that a distance they mean to travel is actually shorter or longer than it appears on the battlemap (I have mechanics for these differences - you roll a die when moving and based upon the result lose or gain movement). You might see an identical flock of birds fly across your path twice in short succession.

The Cenobite like constructs are to this realm what the Archfey are to the Fey Wild. Long ago, Modrons on the Great Modron March ventured into this realm and encountered ... something ... reaching from the Far Realms into the Ethereal. This twisted them and infused them. The simplest of the Modrons because semi sentient features of the realms, each with one, two or three mad purposes. T greater ones became ... curious ... about the universe around them with no morals to guide their actions. They discovered that fear, anguish and pain created curious ripples in the universe that they could manipulate ... and thus began to lure intelligent creatures to their realms to torture them for eternity. They can't leave the realm, but their minions can - briefly. The lured creatures are eventually reshaped by the experience and the realm into distorted nightmares.

I'd say more, but everything ties into campaign specific lore from my setting. Chain Devils, for example, are a Diabolic attempt to reform some of these distorted souls.

While I think my ideas are not a perfect match for what you seek, I think the Cenobite idea might have some legs for you. They are a terrifying presence and their distinct modeling does not strongly evoke a link to a stock plane. While they come from Hellraiser, they are not terribly evocative of the Hells (except for those Chain Devils).

Your splatterpunk constructs have me remember the lictors and other creatures with biomechanical traits from the RPG Kult: Lost Divinity. My idea of D&D cenobites is closer to the chain devils or kytons, although the velstracs from Pathfinder are also an interesting option.

My idea is when Vecna caused the reboot of the D&D multiverse some zones were affected partially. The guild of the chronomancers were saved because they were within certain demiplanes created to avoid the possible effects of time paradoxes. Other areas were left relatively unscathed because they were under time dragons' regional effects (althought this was not intentional). After this the time dragons were "nerferd" or at least a weaker bloodline appeared. The oard (from the adventure "where the chaos reign") could avoid the "reboot" but later they started to suffer a planar invasion of sheens, biomechanical horrors and they are too busy for a long time (and later they were "visited" by the Phyrexians). The "overseers" (It is not a spoiler if I see they are the antagonists from "Tale of the Comet) were affected. Those machines started a rebelion against their creators, the Kir, but this time the strategy was different. The overseers caused a new civil war in the kir world, and then they took the opportunity to escape using a teletransportation technology that didn't work with biological beings. The Rael were "warned" and they tried to avoid the overseers could be reactivated accidentally. The raels could save their world and civilitation but not to avoid the war because the overseers were reactivated accidentally by sheens during a planar incursion.

The fact is a group of "oard" (D&D borgs-like) were attacked and "converted" by sheens, creating a rogue group that was more willing to use magitek. This group started to investigate and they discover the way to use cloning technology to create neuronal tissues for biotechno supercomputers, and the best DNA to create these superbrains were.... the dragons, specially the gem and time dragons. In the begining dragons didn't realise because no coin from their threasures was stolen, only to pick up any fallen scales or eggshells. Later those dragons started to feel something like a "spiritual brother", some type of telepatic link with those biocomputers. Other unexpected consequence those biocomputers could cause some time regional effects. Those biocomputers had got their own spirtis, and believe me, a biocomputer with DNA from gem dragons could use psionic powers. The "oardsheens" who created biocomputers with DNA from time dragons were affected in a different way, mutating, or evolutionating toward time-dragonborns. The guild of chronomancers faced these "oardsheens" and after some confrotations eggs of time dragonborn were found. The time dragonborns from these eggs were adopted by the chronomancers and actually they are loyal members of the guilds.

These "time cybebrains" were created with the intetion to create "space-time bubles" where they weren't affected by the timeline distortions caused by enemy time-travelers, but these coudn't work completely well. This the the origin of the "anomalies", collateral damages in confrotations of biocomputers with the power to wrap reality.