contemporary gloomy gothy stuff:

deadman - additional cause for sorrow https://www.youtube.com/watch?v=5jFl98JbCzI
9goats black out - sink https://www.youtube.com/watch?v=YXA7REzrXBo
the god and death stars - bee https://www.youtube.com/watch?v=KaOFjFeBX68
sukekiyo - immortalis https://www.youtube.com/watch?v=C2PaYV2Dptc

-----

the classics:

buck tick - dress https://www.youtube.com/watch?v=X9lrgSb4edc
luna sea - deja vu https://www.youtube.com/watch?v=EGV5odeAGuM
dir en grey - cage https://www.youtube.com/watch?v=hr1b5v7c4rQ
dead end - good morning satellite https://www.youtube.com/watch?v=AjK-JZUdI-g
x japan - week end https://www.youtube.com/watch?v=0Ja7H5_Kxu0 (you can really see the 80s metal influence here)
kuroyume - for dear https://www.youtube.com/watch?v=aEjAE3WtBbw
janne da arc - more deep https://www.youtube.com/watch?v=plwXTxBG3nk
gackt - mizerable https://www.youtube.com/watch?v=Bt3hamRdncM
-----

weird stuff:

guniw tools - fancy pink https://www.youtube.com/watch?v=lMn4F_y9JiI
metronome - computer https://www.youtube.com/watch?v=eZ4cQcH2n4E (vocals might be a huge turn-off)
caligari - blue film https://www.youtube.com/watch?v=d2goZ1YNZcs
plastic tree - consent https://www.youtube.com/watch?v=KA6z-fAsSGk
merry - kubitsuri rondo https://www.youtube.com/watch?v=EWk3t_70_A8

-----

poppy stuff:

sid - natsukoi https://www.youtube.com/watch?v=megi-V_Rvtc
kagrra, - chikai ni tsuki https://www.youtube.com/watch?v=3rJBZZszZ3A
vidoll - ningyo https://www.youtube.com/watch?v=LIo50_diUFo
baroque - ila https://www.youtube.com/watch?v=F8HNXyzFln8

-----

basically just thrash metal:

matenrou opera - gloria https://www.youtube.com/watch?v=nekJM9IxPO8
nogod - kamikaze https://www.youtube.com/watch?v=lilJSVlUUPk
deluhi - frontier https://www.youtube.com/watch?v=FK2ys_7Ndfk
d - yami yori kurai doukoku no a acapella to bara yori akai jounetsu no aria - https://www.youtube.com/watch?v=H_sspiUcW3o