The only other free icon hider I've found was very glitchy when using full screen apps and moving mouse up to see the top bar. It would get stuck or they would flash in and out again. Bartender has more than what I'm looking for -- just the ability to hide icons. This works great!
It's simple, works great and is free.
Tried Bartender and Vanilla. Vanilla is glitchy and Bartender seems expensive for functionality that is essentially free in Windows 10.
For those comparing this to Bartender, Bartender has more features like temporarily showing an icon for updates/notifications. Useful if you monitor things like Dropbox syncing or connection status menu bar icons.
This however takes the cake for easy of setup. Bartender needs to be configured in the settings panel, and one by one for the icons.
* Homebrew Cask support!
* Very stable (compared to Vanilla, which employed a different method for hiding icons*
I think it would be simpler to employ one "dot" that separates the icons to be hidden/revealed. This can be confusing at first.