I would like to correct @sasavac ISO Czech and Slovak keyboards.
Correct combined design is here: http://www.keyboard-layout-editor.com/#/gists/3425b71498614a6f6f9197cf8af674d4
It's presenting 3 keyboard mappings for Czech (Czech QWERTZ, Czech QWERTY and Czech Programing) and 2 keyboard mappings for Slovak (Slovak QWERTZ and Slovak QWERTY) as You can find in Windows 10.
Keyboard design is based on internacional English keyboard (ISO-US) - left column symbols.
Czech specific symbols aro on right column.
Six keys, where Czech and Slovak keyboard differs have blue symbols in center column.
Because commonly people have installed only Czech/Slovak QWERTZ keyboards in Windows, special symbols like "@", "#", "%"... are accessible by "Alt Gr" + something combination. A that other keys are on some keyboards represented by red symbols.
Some real examples of real Czech or Czech/Slovak combined keyboards I post in thread http://eve.community/t/what-print-do-you-want-for-your-keyboard/2184/47