Bespoke is a free (donaction possible) software modular synthesizer. It contains a bunch of modules, which you can connect together to create sounds.
The ANS synthesizer is a photoelectronic musical instrument created by Russian engineer Evgeny Murzin from 1937 to 1957. The technological basis of his invention was the method of graphical sound recording used in cinematography (developed in Russia concurrently with USA), which made it possible to obtain a visible image of a sound wave, as well as to realize the opposite goal—synthesizing a sound from an artificially drawn sound spectrogram. (more on Wikipedia)
Get a free (donations possible) software version for iOS, Win, Mac from Alexander Zolotov.
Pianobook is a peer-to-peer community of composers, producers and sound smiths sharing their sounds for all to use for free. Set up by Spitfire Audio founder Christian Henson the aim of this community is promote the notion that the best sounds for music are made by people who make it!
Here’s just one example, sounds of the Hohner Guitaret:
Music production on the iPad has come a long way since its beginning. It still lags a bit in comparison to conventional computers but it’s amazing how far you can get with even the standard iPad version of today. Highly recommended for beginning music producers and experienced ones as an addition to their arsenal in the digital music production domain, especially for those on a budget. DAWs on the Ipad are still behind their computer versions but think about how much percent of your DAW do you actually use? Lots of synths, sequencers and effects have completely mirrored iPad versions available and then there are special tailored ones that are only availabe and on iOS. It won’t be long until it will be possible to have the exact same possibilities (and more) on an iPad as on a traditional computer and it’s already totally worth it to use it now.
PS: Image shows Model 15 from Moog.
Fetish is a free compressor plug modeled after analog hardware featuring a filter fro WIN and MAC.