K9-mail on android.
This said, you people are missunderstanding Ralf. In terms of actual production, he is an outstanding knowledge base you do not want to filter out.
To get as off-topic as i can in this Off Topic thread. The best filter is your eyes. Except it's few off-topic threads, as far as i use it, Linux Audio Userlist is primarly about audio. I recommend reading and interating with this list that way, because it is a public list of knowledge-storing that is archived.
Have delicious week ya all.