Key Manager is a more functional version of the program Key Remapper that, in addition to remapping keys and mouse buttons, has many other useful functions.
For example, Key Manager allows you to remap combinations of keys and mouse buttons, key and mouse button sequences, and long presses (press and hold). You can show your actions in the form of pop-up menus that can be opened with hotkeys, record, edit, and execute macros (key sequences), emulate mouse clicks, type and paste text (including formatted text), instantly fill in forms on websites, launch programs, open websites (you can insert currently selected text into their address parameters), change the layout and case of selected text, manage the power settings of your monitor and computer, control the volume or set it at a certain level, move and resize windows, and much more.