Combo Model F for Mac is a freeware organ, modelled after a popular organ from the 1960s.

Features:

Key contacts are velocity sensitive for both attack and release
With a keyboard that has a C-to-C 4 Octave range
4 footage tabs: 4′, 8′, 16′, 2⅔′
With a volume pedal
Knee lever control
6 polyphonic octaves Harmonic range
Bass voice (use the grey keys)
3 treble voices: Principale, Strings, Dolce
Has a vibrato with adjustable depth and speed
Full model, no samples used.
Can be automated
Tweak-able tuning per note

Changes in v1.0.2

• Added Intel 64-bit VST support.
• Bugfix for offline render bug.
• Bugfix for crash in Studio One when bypassing plug-in.
• Automatically select square automation envelope in REAPER for on/off style parameters.

Changes in v1.1.0

• New Larger GUI with 3 views: organ, settings and tuning.
• Better voice filters (brighter, more raucous).
• New leakage to tone generator outputs.
• Extended vibrato speed range.
• Adjusted vibrato depth, which now defaults to light.
• Added authentic noise (mains hum, pink/white noise, chatter).
• Added warning when loading project/preset from older version.
• Updated presets.
• Load/save tuning from/to Scala scale (.scl) files.
• Remember sustain pedal/pitch wheel link when toggling sustain/pitch bend.
• Selecting a tab for MIDI learn no longer changes its state.
• Bugfix for key stealing in FL Studio, Studio One.
• Bugfix for QC LED turning on although tuning hasn't changed.
• Bugfix for GUI width glitch.