There are tons of them - most turn red podded when ripe.
Black Prince , Black Knight , Pretty Purple , Cambodian Ornamental , SBS Purple ornamental , Purple Flash , Fluorescent Purple , Black Pearl , Explosive Ember , Explosive Ignite , Explosive Blast , Black Cluster , Black Cuban...Lot of Variegated stuff too...
Easier to go through Pepper data bases and seed vendor sites to look at pics.
Just put the Species in the search...no name.Look at the pics.
Most are probably Annuums/Ornamentals.
Agree - go through the pepper databases that smokemaster provided links on. However, at least on the chileman database, you can put "purple" in the name, and it will come up with several pages of purples.