Le Portrait De Petite Cossette you just consider Gothic because of the girl imo. it's mainly just a horror supernatural anime with twists. I can't see where you are coming from with Blood the last vampire though. Dark tone sure but yeah not gothic at all.
Comedy has the elements of a true gothic for sure. I'd personally add in Gilgamesh but that's all I can think of off the top of my head. Maybe Dracula: Sovereign of the Damned and Monster of Frankenstein too.
Perhaps taking a look at the Medieval
tag might help you find more anime similar to gothic because looking at wiki i get a sense that it's mainly a book/movie genre and medieval anime tend to have what I think you are looking for from the gothic genre included in them. I'd go so far as searching for medieval and fantasy anime and seeing which titles have both tags attatched