I have tested a lot of freeware instruments but only the best will make it to this list.
Beatzille from u-he is a lite version of the monster modular Bazille synthesizer. Even though it lacks some of its big-brothers features it is still capable of a broad palette of sounds from warm bass to screaming leads and all kinds of crazy sounds and sequences. If you like playing with patch cables you will love Beatzille (and Bazille). I love it! 🙂
Kontakt Player from Native Instruments a lite version of the industry standard sample player Kontakt 5.
Remember to also download the free KONTAKT FACTORY SELECTION which includes 50 free instruments.
All Kontakt instruments from Native Instruments are fully compatible with the free Kontakt Player while 3rd party instruments will only run in demo mode.
Reaktor Player from Native Instruments a lite version of Reaktor 6. It will play all Reaktor instruments from Native Instruments but it require the full version to build your own Reaktor instruments. Included in free player is Blocks Wired and Mikro Prism instruments.
SynthMaster Player Free is a lite version of the powerful SynthMaster from KVR331 Audio. It has very limited editing - only the Easy Parameters may be modified. It sounds just as great as its big brother.
The free version only has 300 factory presets - the full version of SynthMaster Player contains 1100 factory presets.
Zebralette from u-he is a lite version of Zebra2. It has a single oscillator, two LFO's, multi-stage envelope and three effects. Even though it only has a single oscillator it can still create some amazing sounds.