Haha, the fork I was using now tells me that is deprecated and I should use this one.
It is sometimes a hunt, especially when big changes break the plugin architecture or similar. But when it is working (which it does currently for me on Catalina), then it is really nice.
Together with the quick capture of Things, that extracts the url-scheme of an Email, I have a really solid, keyboard-driven email experience.
Many thanks for this!
Unfortunately (but perhaps unsurprisingly), it doesn’t yet work on Big Sur (my personal machine). But it works great on Catalina (my work machine). I may end up sticking with Spark so I have the gmail shortcuts everywhere, but it will be fun to experiment with my workflow.
For anyone else who’s experimenting, I found that wwwjfy’s (the repo creator’s) instructions for enabling the plugin weren’t complete; the terminal command given isn’t enough. I had to use the terminal commands from these instructions from Mailbutler:
I only needed to use the first two to get the “Manage plug-ins” button to appear.
We have a new kid in town:
Native (AppKit+SwiftUI) using GMail’s API (not IMAP). Not much else to say, the full set of GMail capabilities perfectly integrated in macOS.
This is very promising.
I think I’ll give this a try. I hope they plan to release iOS and iPadOS versions.
Thanks for that, looking good!
A gmail client that isn’t just a wrapper around web pages.
None of the other clients pick up the default ‘send as’ email address or any other send as address.
An iOS version would be most welcome 
I tried it. It is promising but without the ability to add non-Gmail accounts it is not helpful for my use case. I’ll reconsider it if they add the ability to add non-Gmail accounts and come out with a mobile version.
I can understand that, both are on the roadmap according to the FAQ
The UI quirks in that article sound really annoying.
That’s a big plus. I wish Postbox was a truly Mac native application. Although I must admit that you hardly notice the difference. Mostly some UI quirks.
I recently came across Missive. It is expensive but very capable. Sadly no trial so I could not test its advanced features.
Wait until you can actually test out Apple Mail for yourself on macOS Big Sur. 
It has some rough edges, though, like an almost baked product: for example you don’t have a shortcut to label and archive messages, or jump to a label. But it’s a one man team and the developer is extremely responsive. I think he’s got a winner in a very specific niche (G Suite heavy users).
I have been corresponding with the Mimestream developer. He is very responsive. Below is an excerpt from his response to my feedback (I referred him to this forum and suggested that he add non-Gmail account capability to the app.):
… I did see that Mimestream was posted on MPU. I don’t think I have an account, but I will make one once I get through the initial wave of feedback, and will try to be available in case there are any questions!
Thanks again, and I’m hoping to have the non-Gmail account functionality in the not-too-distant future. -Neil
Nice One Thanks. I loaded it up over 3 Gmail accounts and >50,000 emails. It did not even break a sweat. Looks like a winner.
I have this app downloaded now, and it’s surprisingly quick. It’s a winner so far.
My favourite is MailMate.
Looks a little dated but very fast, supports Gmail keyboard shortcuts, can add all types of email accounts.
The best part about is how it shows all the past mails when viewing any. Makes it extremely quick to clean up large inboxes.