Igorski has released VSTSID, a free SID synthesizer instrument for Windows and Mac.
VSTSID is ported from WebSID, an experimental in-browser synthesizer for Chrome that approximates the sound of the Commodore 64.
The instrument features full ADSR envelope control, as well as filter cutoff and resonance control, all of which are automatable. There is also a LFO available to modulate the filter.
Whenever three notes are playing simultaneously, the SID will arpeggiate the notes, synced to the hosts tempo. For more abstract sound sculpting, a ring modulator is provided.
VSTSID is available as a free download for Windows and macOS (VST/VST3). A Linux build is currently not provided, though you can build from source.
Also recently released is Toy Piano, a Kontakt instrument library aimed at those who seek to inject some spiky, tuned toy piano sounds into their compositions.
The piano spans a 1.5 octave range and supports multiple velocities for a larger range of playing dynamics.
Another feature consists of the playback of randomized mechanical sounds upon release of the notes.
The Toy Piano library is a free download for Native Instruments Kontakt 4 or higher.
More information: Igorski
Make sure to check the list of Kontakt Freebies for many more downloads.