What do you define as black magic?
The word black magic comes from Khemit, the name of egypt which means black earth. Alchemy or AL-KHEM-Y has, through the ages, turned to a quick, mindless name for "Black magic". However it has continued to take on new meanings in modern times.
Further, there is debate among practitioners of the arts as to what exactly defines black magic. Crowley said that any kind of magic other than finding your Holy Gaurdian Angel tends to become black magic. THat is to say, anything done outside the advancement of the human spirit tends to devolve into what we would call "back magic". Within this frame some view anything done for selfish reasons is black magic. Others disagree and would call it grey magic.
Others consider anything done to harm others, also known as baneful magic, is "black magic"
There are people who follow 'darker' paths and there are those who practice truly maelevolent and evil ways. It is quite unlikely that you will find one who has any desire for a pupil although some might, for a price.
The depths of the blacker arts do include human and animal sacrifice, grave robbing, necrophilia, blood offerings...
If that is what you are really attracted to and feel a spiritual desire to follow this path I would suggest you first do some work to get your head clear and focused because searching for such stuff on a website as vanilla as this is a laughable waste of time.