Mamo

妃阿甦 (THE PIASS) , ∀NTIFEMINISM, Malice Mizer, Aliene Maφriage, Deshabillz

90's bands

Like The Piass + Antifeminism (Punk Rock / Melodic Metal / Hard-core Inspired):

ガラス: Late Matina band, more happy punk than the Piass were but I really loved the one album they put out.  I'm having a hard time finding them on YT, but here's one of their songs for reference (not my favorite one, but it's the only one I could get : / ) 

Vasalla: A soleil band that was pretty influential. Kind of an off-brand X at points, but later turned into a more frilly goth band. This example is when they were more glam metal

Like Aliene or Deshabillz:

*Note: this in terms of spookiness and melody. I don't know of anyone else who sings like Kyoka, so don't expect bird noises lmao

Eze:QuL: a Matina band that had a lot of demo-tapes and solid song writing. You could argue they had some similarities to Deshabillz as well, based on how powerful their guitar melodies were.

L'yse:Nore: Dark 90's vkei, often time melodic and kind of haunting. They didn't use harpsichord or church music. Crystal Wall is a near perfect album.

I know you like Riku (Chariots / Lin / Mago / etc), so consider these as well:

DreqixRudra: kind of like Hiskarea 

Mist of Rouge: D=out's vocalist's first band. Their early releases were a fucking mess because they were trying to fit in with all the goth bands signed to the label and sucked at it (Lubis Cadir (proto-12012) ran into this same issue too). Eventually they learned to change their style and became more punk-inspired and ended up selling super well.

Chelsea: Don't really know much about them, but I do know I really liked Erina's (of Dio and VII-Sense fame) guitar melodies in Sally and Azalea. This is really the only song I know by them, but it slaps so here you go