ihavezippers,
All of the different types of stones covered in the links I provided on stones, tiles, etc. should work without any problem. However, you do not want to use any glazed tiles. They should always be unglazed. Most stones and tiles will require some pre-seasoning. In most cases, commercial stones come with general instructions for seasoning the stones. If you decide to use tiles, I would just heat them in the oven for about an hour, starting at a low temperature and gradually raising the temperature in steps over the hour period and ending up at about 500 degrees F. That should drive off any gases. After that, you should be good to go.
There are undoubtedly other materials that you will find at Lowe's or Home Depot or similar stores that you can use, such as pottery trays and bricks, etc., but I have never tried using them. I wouldn't use them unless I have been convinced that they won't emit noxious fumes or gases. Also, some standard materials may be too thick and require excessive warm-up times to get them to the temperatures needed to bake pies. Unfortunately, you are unlikely to find personnel at the home improvement stores who will be able to answer the question of suitability of their materials for baking pizzas in a home oven. Many of them don't even know that unglazed tiles can be used for that purpose.
Peter