There would be too many snake oil vendors to list.. there are literally thousands of charlatans in this industry all ready and waiting to fleece the next newbie trading 'sucker that is born every minute'.
I don't know if Covell has a system per se, but the trend followers he seems to promote are more likely to be profitable over time than a Hershey Drone. Hershey's stuff will waste countless hours of time trying to decode, just like Gann's, as the Kool-Aid drinkers try to squeeze blood from the proverbial turnip.