Toy hammer and mouth moving dinosaur are great for cause and effect.  When pressing one end of the hammer the eyes move on the other side.  When pulling on lever the dinosaur opens its mouth.  How fun is that!

Musical cow is also great for cause and effect and has a variety of musical functions.

Little Einstein musical toy is a great toy for little hands to hold and explore.  

Bead maze also has some rolling parts that give audio sensory feedback.  Great for exploration and cause and effect. 

Pull along turtle is such a fun toy.  This is part of a complete toy.  I could not pass it up because I love the pulling function on its own.