Are there any unused secure hotkeys?

Question

linux

Lord. There is a keyboard and mouse with macro buttons and internal "memory". With the help of software from the manufacturer, you can set key combinations under the guise of macros so that when you press the button, several are simulated.
The task is to come up with a dozen or two hotkeys that are not used in any program, in order to subsequently bind some of the buttons to phpStorm and some to launch applications.
Additionally, combinations should not contain the Alt + Shift sequence (linux intercepts it to switch layouts and it does not reach java applications).
There is an idea Ctrl+Alt+Num 0-9, but I'm not sure if this is a good solution, and the options space is then limited to 10 keys.
Hardware software understands keystrokes such as calculator or mail, although in fact they are not on the keyboard, but does not understand advanced virtual keys like some of this list.
www.kbdedit.com/manual/low_level_vk_list.html
Ideas?
PS
If anyone is interested, Genius Imperator Pro keyboard, Genius Gila mouse. Hotkeys are made in order to save time and simplify deployment, refactoring, class search, code formatting and other routine things in PhpStorm, as well as to run a number of console scripts.
It is possible to set a total of 18 macro buttons, which should be just enough for the most frequent actions.