Let's talk about this guy and what how strong he might be.
He is Kylo Rens master so anything Kylo knows Snoke knows so That's a given.
He dominated Rey, though new sources reveal that despite her raw power she still is inexperienced with it.
We know that Snoke knows the knowledge that Palpatine wanted to know in the Unknown Regions. With this knowledge, he was able to help the First Order survive against the "Dark things" that inhabit the UR. The UR in Disney Canon is where Force religions like the Jedi and Sith come from and knowledge has been lost since then. He is also said to be strong in the Force and a master of the dark side.
However, despite being a powerful master of the dark side and strong in the Force, his body is so broken and painful that unlike Palpatine he needs his Praetorian Guards to help him in case of violent confrontation. We caught a glimpse of that IMO when Kylo tried to fight and got struck by lightning with his Guards coming in to protect him a moment later.
We also know in his youth he was a strong warrior and he defeated legions of enemies and also that he far stronger than Vader and Palpatine thanks to his "Endless Resources" both things were said by Andy Serkis, Snokes actor. The endless resources thing can be intetpreted in a number of ways.
That's all we know on Snokes power at the moment. Palpatine apparently sensed something so powerful in the UR he actually believed it was the heart of the dark side. Originally people thought that might have been Snoke but thanks to the new novel plus how he died that might be no longer the case. The new novel being "Thrawn: Alliances" this might be connected to the dark things mentioned in the UR. We might see books talking about this post episode 9. In the novel there was this weird.species kidnapping force sensitive Chiss to try and make an army of force users. Not connected to Snoke but in case you were interested.
__________________ "Vader's pulse and breathing were machine-regulated, so they could not quicken; but something in his chest became more electric around his meetings with the Emperor; he could not say how. A feeling of fullness, of power, of dark and demon mastery -- of secret lusts, unrestrained passion, wild submission -- all these things were in Vader's heart as he neared his Emperor. These things and more."
Well, he also created an extremely powerful force bond between Rey and Kylo. That is impressive. He seems to have been planning to take over the Galactic Empire after Palpatine’s death, so he is probably serially smart. I know Wookieepedia is not a source, but it does say that he is a great tactician and helped the First Order in battle strategies to protect it from UR. Luke Skywalker was fearful of him, saying he could not save Kylo from Snoke because Snoke’s grasp was too powerful. He also told Rey that he can’t beat the First Order and Snoke. He points at Snoke signifying his fear.
As for the force connection between Kylo and Rey, im not convinced he created it from scratch. Given Reys power was a Force reaction to Kylos, so it seems to me there was likely already something there.
That said, Rebels Maul seemed to have linked Obi-Wan and Ezra somehow so.... there is that.
That is true, but Maul probably pulled Luke and nearly died afterwards! (sarcasm) If this was the case, Kylo and Rey would have bonded in The Force Awakens, but they didn't. Snoke created it to get Rey to come to him, he thought that Ren wasn't capable of doing it.
I won't at all be surprised if Snoke is revealed to be a Grysk Master, tbh.
*Snoke hails from the Unknown Regions. The Grysk also hail from the Unknown Regions.
*The Grysks' physical features were left intentionally vague, but they were described as: "a wide-shouldered creature with angled brow ridges, a tapered skull, and deep-set eyes." While there was no mention of them being unusually tall like Snoke is, the other physical attributes certainly mesh with Snoke's features. Moreover, only the low-level underling Grysk were depicted in the novel -- but it was stated that they had 'Masters' that were overseeing everything that had transpired.
*Per the TLJ novelization, Snoke was intimately familiar with the Unknown Regions(along with the "terrors" that lurk within it), and was able to save the Imperial remnants that had fled there after the events of RotJ/Aftermath. The Chiss use the precog of their force-sensitive children to navigate through the UR, so perhaps the Grysk do as well... Perhaps Snoke is one of their force-sensitives -- that might explain why his psionic abilities/precog were so impressive. /shrug
*Snoke had evidently "watched the Empire rise and fall". The Grysk have been surveying the Republic/Empire since the Clone Wars, and I highly doubt they had stopped surveying it by the time the Empire fell.
*I would assume the Grysk have also been specifically surveying Palpatine and Vader in particular(especially after the events of Alliances, wherein Vader was wrecking droves of Grysk soldiers)... And that might also explain why Snoke was fangirling over Vader in TLJ.
__________________
"I am tired of Earth. These people.
I am tired of being caught in the tangle of their lives."
I actually thought that possibly the Gyrsk themselves were the Dark things Snoke fended off but your idea works as well. I'm starting to get into the belief Snoke may be just a human, what source does it say he was Humanoid again? TFA novel? Considering how certain things got retconned I'm starting to think so. Also rough drafts in TLJ were going to reveal for hin to be human.
__________________ "Vader's pulse and breathing were machine-regulated, so they could not quicken; but something in his chest became more electric around his meetings with the Emperor; he could not say how. A feeling of fullness, of power, of dark and demon mastery -- of secret lusts, unrestrained passion, wild submission -- all these things were in Vader's heart as he neared his Emperor. These things and more."
It also states in Wookieepedia that he is a humanoid, but that is not saying much source wise. Better than nothing though. Why do you think Snoke was fending off the Gyrsk, any reasons or are you just saying that because they are one of the many, MANY forces in UR.
In SW, humanoid is a very broad term that simply refers to most upright/bipedal species in the mythos. Rukh, for example, is classified as humanoid, and he obviously isn't near-human.
A true 'near-human' would be a character like Dryden Vos.
__________________
"I am tired of Earth. These people.
I am tired of being caught in the tangle of their lives."
Yeah but like I mentioned the TFQ novel can be retconned like the Rey and Poe meeting as an example. Ofc I'm certain Snoke will be an alien rather than a human but the human part is still a possibility.
__________________ "Vader's pulse and breathing were machine-regulated, so they could not quicken; but something in his chest became more electric around his meetings with the Emperor; he could not say how. A feeling of fullness, of power, of dark and demon mastery -- of secret lusts, unrestrained passion, wild submission -- all these things were in Vader's heart as he neared his Emperor. These things and more."