Originally Posted by sirgolf82
I am trying to figure out which fare classes fit the bill for "unrestricted" and "fully refundable". So far, I've gathered that Y, B, K are "refundable".
Not necessarily. There are Y/B fares that are not refundable and non-Y/B fares that are. There is no set "refundability" by fare class. You would need to look at the detailed fare rules for any specific purchase.