Inbox (literally Google Inbox) has this built-in concept of Reminders. You can do it from the desktop app:

It saves you the annoyingness of creating a new email, typing in your own email address, choosing a subject line, and all that.

It’s even more awesome on mobile:

I email myself a lot (or the concept of it), and I was really lamenting the loss of Mail To Self, which shut down after they couldn’t comply with GDPR. This has entirely replaced that for me and I think I like it even better.

Yes, this is an obvious and simple thing, but it wasn’t until maybe a month or two when I even bothered to try it. For some reason, I just avoided this feature, always choosing to email myself instead. It’s easy to learn one thing and do it forever, so it feels like to break the mold sometimes and find a new little workflow you like even better.