BiffCo was a corporation founded by Biff Tannen after winning millions at various sporting events through the 1950s and 1960s. He invested in toxic waste reclamation and other heavy polluting industries with the company. His position within the company gave him considerable sway over legislature, law enforcement, and other influential personnel.
This organization was a key component of the Biffhorrific Hill Valley and was thought to have been eliminated shortly after Marty McFly and Dr. Emmett Brown travelled back into the 1950s to get rid of the copy of Gray's Sports Almanac that was the source of Biff's initial wealth. (Back to the Future Part II)
The company of BiffCo would be the staging area for Biff's expansion into the other worlds of the multiverse, while he was under Armus' thrall. Many of his warehouses would house Heartless and Nobodies which prowled the streets searching for the hearts of vagrants and other such lowlifes to consume. (Star Trek: Voyager - Dark Realm)