This app was mentioned in 2 comments, with an average of 2.00 upvotes
If you like K-9, you'll love Kaiten!
https://play.google.com/store/apps/details?id=com.kaitenmail&hl=en
> Kaiten is based on the popular open source app K-9 Mail and was built by K-9's lead developers Jesse and Chris. By buying Kaiten you not only get an awesome email client, you also support the open source version because almost all of the new features are contributed to K-9 Mail.
Try Kaiten (by one of the K9 devs) if you like K9's feature set but want a better UI.