Logic: The Drill by Nicholas J.J. Smith and John Cusbert.

Free 300 page PDF that contains a variety of solved exercises from propositional and predicate logic. Description from the authors:

One obvious use of this work is as a solutions manual for readers of Logic: The Laws of Truth—but it should also be of use to readers of other logic books. Students of logic need a large number of worked examples and exercise problems with solutions: the more the better. This volume should help to meet that need.