What can a small gym or studio send members in December?
A personal recap of their year works well because it is about them, not about you: how many classes they came to, their favourite class, their busiest month, and how they rank among your members. Members like seeing their own effort counted, and it gives you a natural reason to invite them back in January, when people make new plans.
You do not need a designer. Export your visits from your booking app as a CSV, make one card per member and send it with a short thank-you message.
Keepsake makes the cards from your export, on your own device; nothing is uploaded.
Try KeepsakeHelp: grapnel.team@gmail.com