I've been blessed with relatively few airport floor overnights compared to all the flying that I used to do.

• Some form of boredom reduction, such as books to read or movies to watch on a mobile device.
• Comfortable earplugs -- maybe I'm more sensitive than most, but earplugs that I can wear on a job site just fine won't work for me when I'm trying to sleep. Finding a good pair that I can sleep in was a huge relief.
• Being able to put in a fresh pair of contact lenses, plus contact lens solution. I always carry eyeglasses, but I prefer to not wear them.
• For me, a lightweight packable jacket gets more use than a dedicated travel blanket, but I won't judge you for preferring to carry one. During cold months my jacket isn't all that lightweight or packable, but I'm still carrying it.
• Spare socks.
• My travel power strip with both 120V and USB outputs gets constant use.
• Wet wipes or similar.

As much as possible, I try to fly direct without connections. This seems to vastly reduce the probability that some kind of Airline Unpleasantness will happen to me. This is, of course, hard to do if you're not flying to or from one of the airline's hubs.