Bast

Bast—or Bastet—is the Egyptian Cat Goddess, typically appearing as a woman with a cat's head, though she can appear as a regular person or a regular cat (large or small) as well.

Children of Yog-Sothoth

The Children of Yog-Sothoth—previously Sons of...— are the result of Yog-Sothoth mating with a human female. The most famous of these progeny are Wilbur Whately and his twin brother from The Dunwich Horror, in which instance one was born as a mutated human while the other was a giant, invisible monstrosity.

Great Race of Yith (New)

In prehistoric Australia, the technologically advanced Yithians were attacked by the Flying Polyps. In order to escape, the Yithians transferred their minds far into the future. Unheroically, they traded places with a race of hive-minded insects, leaving them (undoubtedly confused) in the Yithians' old bodies in the midst of the Flying Polyp war, never to be heard of again.

Travelers

Much like the Shan, Travelers invade a host's brain and take control of them. Unlike the Shan, however, Travelers are physical beings, and enter their victim's body through their mouth. They start off in a larval form (shown below) and mature once inside the host. Unlike the Shan, however, Travelers can't easily vacate their host.

Star-spawn of Cthulhu

Cthulhu's spawn are basically just smaller versions of himself. Some were trapped in R'lyeh when it sank, though many were not.