I saw this fragrance called Freak by Illamasqua and it had an interesting note pyramid, containing a few poisonous florals but I found out it was discontinued, are there any fragrances with this kind of concept? Please let me know!
Fragrances with poisonous florals?
Quartana has a series of fragrances themed after poisonous florals ( Midnight Datura ,
Bloodflower ,
Hemlock , and so on) but I think these are more artistic representations of the poisonous flowers than they are replicating the actual scent.

MorganleFay
Ormonde Jayne has a bunch of beautiful perfumes that use hemlock.
I'm not sure how close it is to what you're looking for, but there's angel trumpet note in Ricci Ricci and its' variations
Ricci Ricci Reflets Mystérieux and
Ricci Ricci Dancing Ribbon. Granted, I haven't sniffed them in ages, but when I was 14 the original Ricci Ricci smelled perfectly alluring and gothic to me (*´▽`*)❀.
Quartana has a series of fragrances themed after poisonous florals ( Midnight Datura ,
Bloodflower ,
Hemlock , and so on) but I think these are more artistic representations of the poisonous flowers than they are replicating the actual scent.
Midnight datura looks like something right down my alley, are the clones cloves and the boozy notes noticeable?
Hexensalbe (belladonna)
Black Datura (datura)
Oh yeah Freak Eau de Parfum is really an amazing fragrance, such a shame that it was available a very short time only. Luckily I still have an almost full bottle myself, it smells floral but quite dark at the same time. Smell-wise it reminds me quite a lot of
Secret Obsession. I don't believe that there would be any fragrance with exactly the same concept and similar floral-dark smell, however I find the concept of
Vampire Blooms Cologne quite similar in the sense of forbidden/poisonous flowers, the smell of it is a lot brighter white floral though. Darker forbidden flower themed fragrances would probably be
Smoky Poppy and
The Scent Elixir for Her.
Fame also has this darker concept and a belladonna note, however it's quite sweet smell and also unfortunately discontinued.