I like working in the late evening, but sending emails in the middle of the night may seem weird to our clients. But putting a reminder in my calendar to remind myself to send the email at the exact time I wanted didn’t seem ideal, so I wanted to look for a lazier way to schedule my emails in advance. Since I use Gmail, I’m happy to have found a way to do that using Boomerang for Gmail.

It’s a Chrome extension, but you don’t need to leave your computer on for it to schedule your emails. I suspect it just uses the Google API to do the scheduling.
It even has a feature to remind to you to send follow up emails if your recipient hasn’t responded to you after a certain time. I haven’t tried it yet but I can see how useful it would be for doing outreach.