The Hammond B3 organ.
Additive synthesis at its best !
Suitable for Jazz, Rock, Gospel, Blues, Ballad, House, Funk, Cheesy reprise of anything, Ballad, Dance, Pop, Hard Rock, etc.
Some history here : http://theatreorgans.com/grounds/docs/history.html + some facts

i have selected 7 free drawbar organ VSTi emulations of the Hammond B3.
Let’s groove :

Best Free Drum VST My mother always told me “march to the beat of your own drum”, but I guess she was wrong, because I found a bunch of really good free drum vsts. Amongst them, is the T.REX 606, a classic sound that could have easily cost hundreds of dollars, but for some reason is free. The best Free Music Software Freeware, VST,VSTi,AU,RTAS,Plugins,Instruments Download.

1. AZR3 by Rumpelrausch

Not only free, it’s also open source.
This is a very good drawbar emulation, with onboard FX, nice saturation, and the speaker leslie emulation. Perfect for emulating gospel organ and rock organ. And check the “NHL” preset!

WhiterShadeOfPale
https://blog.wavosaur.com/wp-content/uploads/2014/11/whiter-shade-of-zr3.mp3

As all the other plugins in this list are 32 bit, it could be nice to compile a 64 bit version.
** EDIT** => here is the 64 bit version for Windows : download Azr3 B3 organ VST 64 bit
and the sources

There’s also a MAC version here

Free vst soft synths. Most people tend to underrate free software because they think that if they were better, they would be able to sell them. However, Helix is an excellent Synth that should be used in every serious music production. Download it for free here. Interested in free compression VST plugins? Here’s a post about the 12 best ones. Synth1 by Ichiro Toda.

2. Organized Trio

Free Vst Cab 64 Bit

Organized Trio VST

Present in the same package as “Mr Ray”, it’s the perfect companion for your funky tracks.
And of course it can do the perc dance organ “ala” Korg M1 :

Gypsy Woman:
https://blog.wavosaur.com/wp-content/uploads/2014/11/Gypsy-Women-Organized-Trio.mp3

3. NubiPlus by fxPointAudio

http://www.fxpointaudio.com/ & download

Nubi Plus VSTi come with a VST FX for adding the Leslie effect : Spinner VST. The two make a super groovy combo, and gives you this nice Hammond B3 organ sound.

Free Vst Cab 64 Deluxe

She’s just like you and me, but she’s homeless:
https://blog.wavosaur.com/wp-content/uploads/2014/11/Gypsy-Woman-NubiPlus.mp3

4. DirtBag and LightBag by Istvan Kaldor

LightBag II VST

Good old Synthedit creations : the sound is dirty like it should. You get a nasty B3 organ sound in an instant. Leslie speaker effect is included. There are also some nice reed emulation sounds. And some crazy wicked presets in dirtbag too!

Whiter shade of Dirtbag :
https://blog.wavosaur.com/wp-content/uploads/2014/11/whiter-shade-of-dirtbag.mp3

5. Euthymia VST by Iliadis

This free organ VST has a clean sound. You can add a Leslie speaker as free external effect : iSpinner VST

6. OddlyOrgan by OdO

Oddly Organ

A little more synthetic, you can go creative with this VST !
You can also find other organ VSTis made by OdO

7. VL122 by AM Music Technology

info & download

Discontinued & free drawbar organ : it sounds nice, it’s clean.
You can switch off the motor !
It includes the famous Leslie effect, and also a reverb.
+ a tube/drive effect for more dirty sound.
Cool jazz organ presets.