The golden age of "Mallu Masala" is inseparable from the legendary rivalry between and Mammootty . These two superstars turned the commercial format into an art form, building dedicated fanbases.
(1991) – Not B-grade, but a mainstream art film. You might be confusing with adult B-grade films titled "Kanavu" or similar sounding ones. There is a known low-budget movie "Kanneerum Kinavum" etc., but not truly B-grade.