Not sure who sent the some of the wedding gifts....?

Something similar happened to me. Someone put a card with the wrong gift and I sent a thank you card to the couple I thought had given it to us. They read the card and immediately told me I had thanked them for the wrong gift. So I thanked them for the proper gift and to this day (almost 3 years later) I still have no idea who gave us the other gift. I feel bad that I didn't get to thank them but I had a huge wedding, including a lot of out of town guests, and have no idea who it came from. I hope they know we appreciated their gift but there's nothing I can do at this point so I had to let it go.