IceWM, the venerable X11 window manager, has released a new version, bumping the version number to 4.0.0. This release brings a big update to the alt+tab feature.
The Alt+Tab window switcher can now handle large numbers of application windows in both horizontal and in vertical mode. Type the first letter of an application class name in Alt+Tab, to select the next instance window of that application class. Select an application by pressing one of the number keys. Select an application by mouse in Alt+Tab in horizontal mode. Support navigating the quick switch with all navigation keys. Press the menu button on Alt+Tab to open the system menu. QuickSwitchPreview is a new mode to preview applications. These previews are updated while the quick switch is active.
↫ IceWM 4.0 release notes
On top of this major set of improvements to alt+tab, there’s the usual list of bug fixes and small changes, as well as a bunch if updated translations.

I like IceWM but sadly it is another x111 window manager destined for the dustbin of history. As Wayland only apps eventually appear in numbers, a system that cannot run those apps becomes less and less viable.
Maybe Phoenix or 12to11 will save the day and it will be possible to run Wayland apps on an X server. Before Phoenix, I would bet against it. But who knows?