The Emulator 1 of DSE is an emulator clone and it is Free. It has a lot of sounds of the original Emulator and some easy to work with extras.

Vienna Symphonic Library is software that orchestral and film score composers use. They now released a free set called The Big Bang Orchestra.

SequenceAir of Full Bucket is a very surprising step sequencer which comes with some great features that are very useful for synthesizer musician.