Thanks for the tip, I looked at how to make a custom pie menu, but that involves already too much programming for me. – I am more of an Artist.
But I found an existing addon pie menu for the node editor, that seems to work fine. Although the original list menu would be even more convenient to locate the individual items, I believe.
https://blenderartists.org/forum/showthread.php?414035-ADD-ON-Pie-Menue-Node-Editor