We maintain a PPA for Geary, a lightweight conversation based mail client in the Gnome project with builds for Ubuntu in hopes of making the upstream releases more available to Ubuntu users. You can learn more about the details on how this project came to life here.
You can find the PPA below:
https://launchpad.net/~hkdb/+archive/ubuntu/geary
All the work is stored and tracked at the below link:
https://gitlab.gnome.org/hkdb/ubuntu-geary
To keep up-to-date with announcements and changes, follow @3dfosi on twitter!