Can I find something like these (rubber mats/ sheets) in Divisoria? Where in particular? Wanna start DIY crafting my baby's play corner :)

You might want to try visiting the ground floor of 999 or 168. They have a lot of artsy stuff inlcuding materials for DIY which you can buy in bulk (with more discounts than retail purchase) especially if you are working on a larger area like your baby's play corner. If you don't want to travel far, you can also purchase assorted rubber sheets in National Bookstore. I purchased some before when I did a DIY for my nephew's birthday party. It was around 100 pesos per pack.