I second Songsterr and Ultimate Guitar, although a lot of the time the tabs on there can be inaccurate or unfinished, and I see this a lot with Vkei tabs. In those cases, it’s good to find decent playthroughs of whatever songs you want to play.
This channel has some pretty good guitar playthroughs of various Vkei songs.
We also have this.
I write a lot of guitar tabs for my personal projects, and I wrote a few tabs for some Mejibray, Deviloof, and Arlequin songs a while ago, just for fun. I might start doing that again, upload them to Ultimate Guitar, and maybe post them here for anyone who’s interested, and also maybe to get a list of songs that haven’t really been tabbed out yet. I still haven’t found proper tabs for Anata no Tame no Koni Inochi by The GazettE yet, so that might be my next project.