I strongly believe that Supreme Leader Snoke is a new character, but some of these Star Wars theories are so juicy, I just... can't ignore them, mate. While some are bloody stupid, some are smart and do make some sense with legit back-up (Especially the Darth Plagueis one).
But let's countdown the 5 Top Theories on who Snoke might and really is.
#1: He's A Reincarnated Palpatine
While I do believe Palpatine is long gone, some fan has said that Snoke can jump from body to body, and that Palpatine was under Snoke's control the whole time, and when Vader threw him down that shaft or something, and we some weird force power being released after that, it's simply Snoke's force spirit being released and searching for a body.
Huh? Cool theory, but I think it's ridiculous enough to write it off.
#2: Snoke Is...(Drums Playing) Jar Jar Binks!
I mean, this doesn't need explaining on why it's stupid, it's just....I get it that it's a parody theory but people taking it seriously and making cases for Jar Jar being a Sith lord, it's just so stupid, man!
#3: Snoke Is A Time Travelling Kylo Ren....?
It would be so stupid if Star Wars introduced time travel. It's the ultimate Deus Ex Machina.
But the theory goes Kylo Ren came to the past, as Snoke, to train his younger self so he doesn't fail or something.
I dunno, that's what the theory is. And it's stupid.
#4: Snoke Is Darth Vader...Somehow.
Snoke is being theorized as Vader, because of the scars....That's it, because of the scars, nothing else. If I had a small scar on my finger, and someone else had the same scar on their finger, does that make us the same person? Bloody no!
#5: Snoke Is Darth Plagueis
This one is probably the most well thought one. They both have the same reasons to re surface and they have the same themes, and it will tie the three trilogies together, cause Plagueis impregnated Shmi with the Force and conceived Anakin, and then Anakin and Padme conceived Luke and Leia, and then Leia and Han concieved Ben Solo/ Kylo Ren and then Luke and (hopefully) Mara Jade conceived Rey, whose the new protagonist of the new trilogy, making Plagueis the one kicking off the events of the Star Wars saga.
Snoke is just Snoke, why can't we have new characters? Although I would rather prefer Snoke being much more than just a random big pointless villain.
Snoke Is Just Snoke