I would suggest one of these acrylic enamels.

DELTA PERMENAMELS - Air-Dry, can be used on glass, tile, and ceramic, requires no heat setting and is non-toxic, oven, microwave and dishwasher safe. Uses 3 steps - surface conditioner, paint, and a glaze finish.

DECOART'S ULTRA GLOSS ACRYLIC ENAMEL - weather resistant, non-toxic, and no baking is necessary for a hard durable finish. Uses one application - no surface conditioner or topcoat.

PLAID'S APPLE BARREL INDOOR/OUTDOOR GLOSS ENAMEL - non toxic, weather resistant, suggested it be baked on tile, glass and ceramic for more durability and wear.

*Even though all of these paints are non-toxic it is suggested that the paint never be used on a surface that will come in contact with food. So if painting glass plates for use, you might want to paint your design on the bottom side.

About the kind of paint to use on mirror? I am interested to know about it....for I am thinking to fix the bottom of the bathroom 9 years old mirror that became grey and I thought may be I could paint some designs to hide it...
THANK YOU

I use apple barrel paints to paint on wine glasses and vases .It works well and is easy to use.