Adiós is to help you deal with email less: 

Adiós brings your emails into your inbox just 3 times a day, so you can get sh*t done.

I’m not entirely sure how it works, but it appears to be a Gmail-only thing that you just have to authorize and it does it’s thing. They promise to not look at the content of your email ever. The setup processes looks quick, easy, and configurable. 

This is curious to me as it doesn’t really help deal with email overload. It seems to be more about email addiction. If you find yourself poking around in your email too often, this could help. But if that’s the case, I wonder if delayed-then-bulk delivery is really a solution? Especially since surely it’s easy enough to turn off. The present some interesting light data though (no sources):

The average person checks email 74 times a day! That’s astronomical, given that most emails really aren’t that time-critical.

And it’s not just the time you spend reading and responding to mail – it’s also the time and mental-energy you expend context-switching.

Being interrupted during a focused task and then trying to context-switch back to focus on it again can take 20+ minutes before your mind is fully back in the zone again being productive.

In any case, it’s free and easy, so perhaps it will appeal to you.