Googling for IOR values can be dangerous! There’s all kinds of funny videos, facts and troll comments just waiting to steal your time. IOR Reference is an addon for Blender that adds a list of common IOR values right in the nodes editor. It has over 300 values so you can avoid the web browser and stay in Blender (and “the zone”).
It also includes a button to insert a value node with the selected IOR. Most times you can just type it but it can be handy if you have to plug the same IOR on different nodes. Also as with all UILists in Blender, you can search and sort the list by clicking the plus icon at the bottom.
You can fork it on github or download it here.
Download IOR reference