Dromaeosauridae includes some of the most fearsome killers of the Cretaceous Period: Deinonychus, Velociraptor, and Utahraptor. The largest known of these was possibly Utahraptor, and Microraptor was among the smallest (40 cm or 16 in).
Troodontids date from the late Cretaceous Period and were lighter and slimmer than the dromaeosaurids. Some of these were Troodon and Saurornithoides.
By some definitions, Deinonychosauria and Dromaeosauridae are synonyms.