Five years ago, I would've responded with TribeTwelve. I loved the black and white aesthetic, the way Slendy's tentacles look, the idea of Slender Man taking on the form of a spider, etc. The campy style of acting added a lot of charm to it.
However, due to what came out about its creator, Adam Rosner, back in 2020, I can no longer look at that series the same way. I'm sure I don't need to explain why.
Currently in 2024, my favorite series is MorleyGrove. It's an interesting interpretation of Slender Man and since it's made by the same guy who made Gemini Home Entertainment, I have high hopes for it.