Thank you cards

Hello all - My fiance and I opted to not have a registry and in lieu of gifts we asked that if they really wanted to contribute, our guests could make a donation to one of three organizations that we included on our wedding details card. We don’t know who has contributed unless they let us know. For those that we know of, we will send thank you cards. But should we send thank you cards to all guests thanking them for participating in our big day?