UPDATE! I guess that the number 3300 is the maximum for a letterboxd list. Whenever I add some new movie to this list, it's gone after a few hours. So I decided to make a second list for those few movies that can't be added here. It's not much and the quality of these movies is rather... average. But still, I want my list to be as as accurate as possible.
Here is the list.

It took me few days to made it, but here it is- the biggest 2000's horror movies list ever.

I included few films which were made in 2008 or 2009 according to IMDB, but are marked as 2010 or 2011 here on letterboxd.
Feature films only.

Honorable mention: The Evil Within, movie released in 2017, but shot in 2002.