de la Mancha has released basic 64, a synth inspired by the 8 bit sounds of the "classic" Commodore 64. It's not a straight emulation but is based around the SID chip with some extras for that 8-bit retro game sound, lofi gritty noises or just plain oddness.

Features:

• 16, 8 or 6 bit sound quality.
• 3 oscs, each with their own ADSR envelope.
• Oscillators can be sync'd and ring modulated by each other.
• Pitch envelope modulation.
• Pitch wobble option, for subtle instability.
• 2 tempo-sync LFOs to modulate pitch, cut-off and pulse width.
• LFOs have attack/release curves.
• Tempo-sync arpeggiator.
• Flexible routing to state variable filter (LP, HP & BP).
• Envelopes can be reset or continuous at retrigger.
• Monophonic or polyphonic option.
• MIDI learn / MIDI CC support.
• 128 presets by sinkmusic & WhiskeyPriest.

basic is available as a VST instrument for Windows and it is free.