postmarketOS

is one of the largest and oldest mobile Linux projects. Based on Alpine Linux, it provides a large, up-to-date package selection (on the edge channel) and a secure base.

Benefits:

• Choice of init system and Desktop Environment is yours when installing with pmbootstrap, their easy-to-use flash tool
• Large community and Wiki
• Uses clang C-compiler

Drawbacks:

• Can be unstable (in my Experience, while testing Phosh)
• No Keyboard and Pen support on latest Kernel versions

postmarketOS, 7.0.6
pipa Wiki Web pmbootstrap