I've pre-launched my first Gmail add-on «Silent Inbox» that filters your inbox and delivers email newsletters once or twice a day.
I spent a month to develop it and get approval from Google as the add-on uses some sensitive scopes. Google approved it in 3 weeks of negotiation and updating.
After beta-testing I'm going to launch the add-on on Product Hunt, try to get «productivity» press, and ship a few important updates for Premium accounts.
To check it out go to https://bit.ly/318ApMb.
For feedback leave a comment or chat with me in the add-on.