Big Floors GarageDeck Garage Floor Tiles, Interlocking Garage Flooring, Coin Pattern Non-Slip Heavy-Duty Copolymer Modular Tile (Beige, 48 Pack of 12 x 12" Tiles, 48 Sq Ft)

These remind me of those floor tiles you can get for garage workspaces and such. I'm sure the floor tiles aren't manufactured to as high a degree of precision as tiles specifically meant for glass cutting, but they might be useful if you've already got some laying around, or are looking for a cheap way to make some very large cutting matts. Take a look at the sixth product image to see what I mean. https://www.amazon.com/GarageDeck-Pattern-Durable-Interlocking-Flooring/dp/B0754158TN/