/use2 - this slash command is the same as the "use secondary ability" on the keyboard settings. It's meant mainly for artifacts that might have more than one ability.
/interact - this is how you might read or otherwise interact with a scroll or an artifact. If you've got something potentially nifty, try and /interact with it. See what happens.
There are some other, quest specific commands as well. One of the ladies on the Pendragon board said it best "Rule of thumb: if a quest explanation says SEARCH, PLANT, USE, EXCAVATE, etc., it usually implies that is the command you need to use.