The following list categorizes essential B-movies by genre and era. These films were selected based on their production context (low budget/second feature) and their enduring cult status.

: Films made outside the major studio system, often with modest budgets ranging from $50,000 to a few million dollars. They often emphasize character development, personal vision, and unconventional or challenging themes. Movie Grading and Rating Systems

Films produced specifically for the bottom half of a double bill.

A list typically refers to low-budget, independently produced (or studio second-feature) films, often from the 1930s–1960s, but the term now includes straight-to-video, low-budget horror, sci-fi, action, and exploitation films from later decades.