There`s pretty much two types of tile - the plaster tiles which are usually glazed and the ceramic ones that usually aren`t. Down at the Home Depot there are some 3/4" or so squares of white tiles in a 18"x30" sheet or so and you can tell because the tiles look stronger with sharp edges that you can`t really ding with your key (you can do that to the back of a plaster tile without problem). The tiles are more used for floors and usually there isn`t much of a selection of them. I`ve also seen the tiles in a hex shape and the important things are that they are ceramic and small.
As far as abrasives are concerned, you can get kits or individual grits from a number of places, including a guy that is usually advertising on Astronomy-Mall and other places.
As far as the drill sizes, everyplace that really deals with machining tools has a chart (often a giveaway) on what drill sizes are and many of them also include the sizes of metric drills and the inch size drills. If you get a drill box, the number and diameter of the drills are usually punched on the metal pages. As a bonus, the top page usually has the tap and clearance sizes for the common tap sizes.