A very recent Q & A mentioned a Lutheran church body that is pietistic in nature. WELS is not affiliated with that church body.
There was a Pietistic Movement in the history of the Lutheran Church and, years later, the movement’s influence was felt in the early years of our church body.
If you are interested in reading more about the topic, this link will take you to an essay from the Wisconsin Lutheran Seminary Essay File. This link will provide you with information on two books from Northwestern Publishing House.