In my classroom, I don't plan a lot of crafts. Now that word is tossed around and defined in a lot of different ways. I think of a "craft" as an activity (usually using art materials) that focuses on an end product - the goal is usually producing a particular something.
Most of my art explorations are more focused on exploring the materials or exploring ideas. I may have a particular goal when putting out materials. (We will make a book, etc.) But the kids can use the materials in ways that they choose - following their own ideas as they work.
However, Mothers' Day is one of those times when we shift more to "making something." Our traditional activity is making a magnet. We use cardboard shapes and sticky gems to create. The kids can still explore their own ideas, but they are excited about making something for Mom.
Here are some links for other ideas of "somethings" that your kids could make--
Mother's Day Gifts with Sticky Paper (Pre-K Pages) - Make a bookmark or a suncatcher.
Felt Shape Flowers (B-Inspired Mama) - Practice shape and "build" flowers.
Simple Printed Mother's Day Card (Rainy Day Mum) - Repurpose a plastic bottle to make a flowered card.
Planting for Mother's Day (Teach Preschool) - Plant some real flowers for a springtime gift.
Mother's Day Gifts Kids Can Make (Pre-K Pages) - A roundup of lots of ideas for kids and moms
What other ideas are your favorites for Mothers' Day?