I’d like to see one that is a clearing house for tracking cookies.

It would send do not track with a random pile of tracking cookies from the pool, corrupting the profile data for any trackers that don’t honor the header.

Contract law says last speaker wins, so one could argue the trackers use of the cookie content was unauthorized, so any damages to the tracker companies’ databases are on them, not the user or the extension.

(I am not a lawyer; this scheme is probably risky)

They have the "I am not a robot" captcha before every single box. They thought about it. They engineered a solution against it. They are not even trying to hide the fact that they want to make it difficult.