Don't forget about Inbox, the Gmail spin-off that tries to manage most of your messages automatically. It may not have the traction of Google's primary email client just yet, but it's still getting new features on a regular basis -- including the ability to snooze specific emails until a delivery or event date mentioned in the body of the message.
The new option, which was added a couple of months ago, appears on the standard Snooze menu. Tap the clock face icon with an email on screen, and -- if Inbox can parse the right information from the message -- a time-sensitive option appears (such as the Day of delivery option in the example above). You can also swipe emails to the left in a message list to bring up the same Snooze panel.
Google says the option applies to package tracking updates, restaurant and event reservations, calendar invites, flight confirmations, hotel reservations and rental car reservations. Plus, you can set specific times or even places as before from the same menu. If you still haven't found a reason to switch to Inbox, this could be the feature you've been waiting for.