Toner Transfer Paper:
I love this stuff from DynaArt Designs. I make my PCB artwork on my computer, laser print it to a piece of TTP, iron it onto the board (I use DynArts Superfuser now), soak in H2O for 3 minutes to take off the paper, then etch the board. Just scrub the toner off of the board with steel wool when it's done.

Photo Resist Fluid:
You can use this stuff to apply a layer of UV sensitive photo-emulsion to the surface of any copper-clad board so you can then use a photo process to make a PCB. You can buy chemicals specifically for positive or negative processes, special applicator brushes, etc. Personally, I prefer to purchase "pre-sensitized" boards which already have the coating on them because you get better consistancy in exposure and developing times. Also, after you apply some emulsion coatings, you have to bake them. Keep in mind, you also have to protect them from all UV light during this process or it'll be ruined before you start.

Photo Resist Developer:
After you "expose" your UV-sensitized board, you have to delvelop it. This is because the emulsion coating covers the entire board, masking the whole thing so that nothing would etch. In a positive process, swishing the board around in a tray of developer will remove all the portions of the coating which were exposed. In a negative process, all of the non-exposed areas are removed. After this step, the board can be etched.

Photo Resist Stripper:
After you etch the board, you must remove the remaining bits of the emulsion layerbefore you can solder anything on the board. Swishing the board around in a tray of stripper will dissolve it away.

Tinner:
After your board is etched (and stripped in the case of photo-etching), you might like to swish your board around in a tray of timming solution. Available in powder or liquid form, the solution will deposit an incredibly thin layer of tin metal to the copper on the board. This coating makes soldering easier and resists corrosion better than bare copper. Don't try polishing it after applying it because it won't turn shiny, it'll just rub off.

Ink Pens:
Ink pens are used to create a masked area on a copper-clad board before etching. You can draw whole circuits this way but I wouldn't recommend it if you like neat work. I use them to fill in pin-holes in toner masks left behind by Toner Transfer Paper and making general repairs to a mask. Also, the "official" resist pens are over priced and generally dry up quick, but they do work well. As an alternative, I use a felt tip permanent black marker made by Staedler Lumocolor model# 313.

Conductive Ink Pens:
These pens have silver impregnated ink and are used after etching to modify or repair copper traces on the board. Just draw a wire!

PhotoPlots:
These sheets are clear & black actual size reproductions of your copper circuit pattern. They are used to expose your UV-sensitive boards to your desired pattern. These sheets can be used over and over to make hundreds of duplicate boards. Some photography shops and graphics shops can produce them for you from a laser-print or other drawing of your artwork for about $15 per 8.5"x11" sheet.