For regulars I would go with something from Dungeons Vault Genetics as I have grown a few strains from them and they are very close to the descriptions given.
Haven't really gone after too many strains just cause they were purple, I go for dank and so I fell on DVG by fluke
I believe they will have a drop soon or already had another drop at thedankteam.com
Dark Devil Auto
https://www.dinafem.org/en/dark-devil-auto/
I know it is an auto but it is the only plant I have grown that was completely black and purple. I have honestly never seen anything come close to how dark it was. Only thing is me and my buds only had one seed from a freebie we got on our 420 order one year. But if you look it up you should be able to find plenty of claims to back it up. Only thing is I don't grow autos so I didn't purchase any just on that note.