4 FT X 6 FT X 1/2 IN RUBBER FLOORING RUBBER MAT CONTAINER SHOP GARAGE – Uncle Wiener's Wholesale
Equimat Stall Mats - North America
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 :
IncStores 4'x6' Premium Mat - Vulcanized Rubber Exercise Mat, High Density Floor Mats for Gym Flooring, Home Gym, and Horse Stall Mat (Gray, 3/8" Thick - 1 Mat), Exercise Mats - Amazon Canada
Horse Stall Mats - Summit Rubber & Coatings
For Living Rubber Indoor/Outdoor Master Mat, Assorted Colours, 3-ft x 4-ft | Canadian Tire