Thanks for the replies.
Specifically, trying to get back to Nigeria. US Passport. Previously I went on a "subject-to-regularization" visa (lengthy process toward resident alien status) and an open paper ticket issued by a TA. Believe it or not, I still have my Yellow Card which is still required according to their gov't website, as well as a host of other particulars.

Carriers would probably be KL or DL. I just wonder if ZED tickets would suffice. Printing out a RT PNR? You've got to figure their immigration has caught on to the cottage industry of creating itineraries and scamming people in the US to send money to pay for the ticket. In other words, proof of confirmed space is not proof of a ticket, obviously. Same for standby.

Next phase is to make sure my life insurance is up to date.