Diamond plates are stainless steel plates with embedded diamond grit. You can get various grit sizes. Fairly expensive. Good for a certain number of sharpening jobs but I think for sharpening knives by hand I prefere whetstones which neatly brings me to:
Whetstones are natural or man made stones used for sharpening. Unlike diamond stones which can be used dry, whetstones need to be thoroughly wet.
Tiles? Not sure in which sharpening context that fits in although I think that might be a part name for a sharpening system called the Edge Faux which is a cheaper version of the original Edge Pro system. It involves clamping the knife down and running different tiles (?) which have differing grit sized embedded sharpening stones set at a pre-fixed angle over the edges.
I prefer using whetstones for kitchen knives although I have used other sharpening devices. If you're thinking of sharpening/honing straights you need'll a whole array of stones.
A serrated knife is sharpened each serration at a time using wet and dry sand paper wrapped around something that is the exact shape (triangular or whatever serration shape it has) of the serration. After you've painstakingly done that you just run the flat side on a whetstone to take the burrs off. I'm assuming you're referring to a bread knife here. If your knife has serrations on both sides of the knife you can still use wet or dry sand paper but think I'd chuck it and buy a new one.
