The FTC’s National Do Not Call Registry is quintessential government mediocrity. Registering a number is clunky, certain types of organizations are given a pass (like charities and political groups), and reporting a violation is a three page slog that can only be done through their website. No thanks.
One particularly creative solution comes from Jolly Roger Telephone Company, which was highlighted on episode 937 of the Tom Woods Show. It’s not an app like the others, but a “robot” that you can pass telemarketers off to (either through teleconference or the “simultaneous ring” feature if your carrier supports it). The robot then carries on a very convincing conversation, wasting the telemarketer’s time and reducing the number of people they get to annoy that day.