When I read your post, I picked up on the fact of 'how' you were invited. Was everyone else invited the same way? Maybe no one got formal invitations. If you really want to be practical, give them laundry detergent, fabric softener, bathroom soap, dish soap. It can add up and they'd really get good use of all of it.
Years ago, when someone was expecting (before I knew how to quilt), I'd give the new parents diapers and wipes...also for 1rst and 2nd birthdays. They all LOVED how practical I was and even requested the same gift the next year. Good luck with your decision.