I use a couple good call lures...some commercial and some I make.
It is really hard to beat a good red fox gland lure for both fox and coyotes. RFG is very versatile at just about any type of set and effective all season.
If a trapper had a good fox gland lure, a good beaver castor lure, tinctured skunk essence, and a sweet food lure (coon, rats), and shellfish oil they could kill all the fur bearers in PA with little need for other attractors.