Here are some ideas from previous editions:

• Make a donation to an association, subject to a target number of challenges to be achieved collectively. Example: 1000 euros donated if our company achieves more than 3000 challenges!
• Plants, seeds, terrariums ... or any gift in the form of plants from your region !
• DIY kits to learn how to do zero waste
• Gourmet gift boxes based on organic and local products from your region

If the lucky winners are based in the same city :

• Invite them to green restaurants/bars. You can use HappyCow to find ideas near you