One that springs to mind straight away is Blodwyn Pig.
Formed in 1968 by Mick Abrahams (who\'d previously formed Jethro Tull along with Ian Anderson).
Anderson wanted to go more down the folk/rock road, but Abrahams wanted to stick to the more traditional blues, so quit Tull. I suppose \"financially\" wise it was a bad move - musically wise - he made the right choice in my opinion.