Inspiration for modern designs can come from anywhere. You may have an existing leaded window with some damage or in need of renovation. It can be rebuilt and adjusted at the same time, perhaps to replace one colour with another.
Images or photographs from the web can be used as the basis for a new design. Very often an initial design needs to be adapted to make it possible to be built or to make the end product strong enough to withstand opening and closing in a door or strong winds, etc.
Certainly, adding a modern stained glass window to your home will give that wow! factor.