Costco (in Canada at least) has these sweet rubber mats that remind me of the gym. Way cheaper than Amazon since they are heavy as heck! It's flat on the other side :
ProsourceFit Extra Thick Puzzle Exercise Mat 3/4 or 1 Inch - Bed Bath & Beyond - 21587890
Rubber Mat 20" x 20" x 20mm - Grey Speckle – Fitness Avenue
Hatashita Standard Puzzle Mats for Club & Home – Hatashita Retail
Hatashita Standard Puzzle Mats for Club & Home – Hatashita Retail
Rubber Home Gym Flooring | Solo Fitness
nuveti Large Exercise Mat - 15mm/20mm/30mm Thick Yoga Mat | Workout Mat for Fitness, Yoga, Pilates, Stretching & Floor Exercises for Women & Men with Free Carrying Bag and Carrier Velcro, Mats -
Non-Slip Fitness Rubber Flooring 20mm Thick EPDM Surface Rubber Tiles - China Rubber Floor, Gym Mat | Made-in-China.com
Source Gym Equipment EPDM 20mm Used Rubber Gym Floor Tiles Rubber Gym Mats on m.alibaba.com
Economy Puzzle Mat - 20mm (Pack of 6)
Gym Flooring Rubber Mat 20" x 20" x 20mm - Grey Spekle : Amazon.ca: Tools & Home Improvement
Rubber Mat 20" x 20" x 20mm - Grey Speckle – Fitness Avenue
nuveti Large Exercise Mat - 15mm/20mm/30mm Thick Yoga Mat | Workout Mat for Fitness, Yoga, Pilates, Stretching & Floor Exercises for Women & Men with Free Carrying Bag and Carrier Velcro, Mats -
Gym flooring – SoftSurfaces
Rubber Flooring Gym Mat 3.0 - Bells Of Steel USA
MMA Floor Mats & Matting UK | Gym Floors Direct
Factory Customized 20 mm EPDM Rubber Flooring Mat for Gym - China Rubber Floor Tile, Flooring | Made-in-China.com
Rubber Mat 20" x 20" x 20mm - Grey Speckle – Fitness Avenue
Premium Rubber Gym Flooring Tile - 3.3ft x 3.3ft | SMAI – SMAI USA