Stamp-N-Storage has their
Bee A Blessing card drive.
Locally, I donate to Meals On Wheels. I make seasonal cards every month for all the meal receivers and the kitchen ladies slip one in to each lunch bag once a month. I do not sign them because the receivers love to use them to mail out to their loved ones.
Ask your local library if they'd like donations of cards to sell as a fundraiser. My local library has a card rack with cards for sale for $5 each. The library keeps all the proceeds.
If you attend church, you could leave a box there for people to take one as needed. I did this at our former church and kept the cards organized by occasion. It was very well-liked!
I donate cards to a local assisted living facility. They sell some in their gift shop and use the proceeds for resident activities and they give some as bingo prizes to the residents. Again, very well-received.
If you like to send cards, there is a great Facebook group called
Sending Sunshine and Rainbows. People send in requests on behalf of others and we can write messages and mail cards to any of them. It's made a LOT of people happy.