University of Ottawa (Canada)
University of Ottawa: Hyper Grammar: Building Sentences
An excellent site which outlines the types of sentences - simple, compound, and complex. Gives in-depth information and examples of each. Includes review exercises for practice or assessment.
TES Global
Blendspace: Compound Sentences & Fanboys
A five-part learning module with links to an image, videos, and texts about compound sentences and the coordinating conjunctions used to form them.