Tapper
Keyboard layout switcher for X Widow System and Wayland
...Tapper key feature is using modifier keys for switching keyboard layouts without losing modifier's functionality. Tapper works for GNOME, GNOME Classic, Cinnamon, i3, KDE, LXDE, LXQt, Mate, Ubuntu, Xfce desktops.
There are prebult RPM packages for Fedora, Mageia, OpenMandriva, openSUSE, source tarball for configure && make is also available.
Tapper is free software.