Hey there! You asked about B movies . . . about a month ago. Sorry for the delayed response. Are you looking for more flicks like Slither? Or just B movies in general? I may be getting too granular in my classification. :)
Just off the top of my head - Teeth, Dead Alive, NIGHT OF THE CREEPS!, The 80's remake of the Blob, Feast, It's Alive, Basket Case, From Beyond, Reanimator, The Stuff, the Deadly Spawn. . .