If you happen to run the Cinnamon desktop on Linux Mint I highly recommend the System Tray Collapsible applet. If you don’t run that exact distro and desktop, this post is going to be really boring for you :)
System Tray Collapsible lets you hide icons in the system tray. It’s probably meant to reduce the space your system tray takes up, but what I use it for is hiding notifications from myself. Slack, for example, adds a little blue dot to it’s tray icon when you have an unread message no matter what your notification settings are. If you’re totally incapable of ignoring a notification like I am, that can get pretty distracting. System Tray Collapsible to the rescue! If you can’t see the icon at all, there’s no blue dot to distract you.
One caveat: it can be tough to get your pointer in just the right place to see the context menu for the applet (which is the only way to tell it which icons to hide) instead of the tray icons inside the applet. Keep trying, it is possible!