Cesium

Given the fact, that it's a free plugin this deserves easily a 5 star rating because A it sounds awesome and B has a super responsive Gui. Thanks.

Cool, extremely flexible chorus (and more) with a really good basic sound, which you can alter very intensely. Sound quality is excellent, the results never sound digital or sterile but very organic and natural.

You can adjust almost everything to your needs, from vintage chorus or even flanger sounds to more modern ones, but you can also adjust some nice, more unusual experimental or spacious modulation sounds.

I think, this is - if properly adjusted - one of the best sounding and also most flexible chorus plugins, which I ever have heard, if not the best one.

Not only for a freeware plugin excellent! Highly recommended.