Tiles (loose layed , no glue no grout - makes it dead easy to remove soiled tiles for cleaning), and some scot-towel (paper towel) under food dish and in places the beardie likes to use as it's latrine or to nap.
In full size beardie enclosures for adults - as above.
In rearing tubs , I cover about 1/2 the the "floor" with paper towelling (2 or 3 layers).
I have tried everything and yes, tiles (removable) are the best. You can usually just wipe up the mess and twice a month or so take 'em out and really clean them.
I would say that without doubt it's non adhesive shelf liner or newspaper....but for the better look of the two it's the shelf liner. Put down 2-3 layers, makes it easier [ softer on the joints ] Or put down newspaper with shelf liner on top. The reason I think it's better than tile is that tile is really not natural as some think. It's harder than the packed dirt + sand they would live on in the wild and it has the potential to cause joint problems in their older years. I've also seen several threads where dragons have unexplained red sores on the bottom of their feet. Tile seems too hard for active dragons that are digging + jumping. Shelf liner is also easy to wipe clean....the smooth type is the best.