This is maybe the first SimSynth free presets pack ever and it contains 26 presets it total.
Personally I often use this plugin so I tried to make some presets for you. First volume containing some basses, pads and strange effects. Enjoy it!
FOR FL STUDIO 8:
C:Program files\Image-Line\FL Studio 8\Data\Patches\Plugin presets\Generators\SimSynth