If you have a tight budget and your gym mats need to do double duty as wall mats you can hang them by using Wall Molding Strips.
How to Remove Command Strips and Hooks
Wide Loop Black by VELCRO® Brand, 12 by Yard and Custom Sizes
SCHOOL SUPPLIES FOR TEACHERS AND EDUCATORS - Numerous applications to keep the classroom tidy - fasten items to desks and folders, stick nametags to
VELCRO Brand Sticky Back Strips with Adhesive | 4 Count | Black 3 1/2 x 3/4 In | Hook and Loop Fasteners for Home Organization, Classroom or Office
VELCRO Brand 16-in Easy Hang Small Strap 16In X 1In 100 Lbs Black Hook and Loop Fastener in the Specialty Fasteners & Fastener Kits department at
Velcro 1 self-adhesive loop, 10 yard dispenser box, tan
VELCRO Brand 4-in Black Industrial Strength 4In X 2In Strips. White Hook and Loop Fastener.01-sq ft (2-Pack) in the Specialty Fasteners & Fastener Kits department at
Hook-and-loop fastener - Wikipedia
VELCRO HANGables Removable Wall Fasteners 3 in. x 1-3/4 in. Strips (4-Count) 95183 - The Home Depot
VELCRO ALFA-LOK 3 in. x 1 in. Strips in Black (4-Sets per Pack) VEL-30643-USA - The Home Depot
Self-adhesive Wall Trim Internal Corner Molding Line Caulk Tape Edge Decor
VELCRO Brand Sticky Back Strips with Adhesive, 4 Count, Black 3 1/2 x 3/4 In
VELCRO Brand Adhesive Dots Black, 500 Pk 3/4 Circles Sticky Back Round Hook and Loop for Office Organization, Arts and Crafts, School Projects
Hook Loop Strips with Adhesive - Melsan Industrial Strength Sticky Back Fasteners Hook and Loop Tape for Mounting, Hanging, or Organizing Items
India String-Or-Nothing