The most typical decorations are like the decorations seen below; sparkles of different kinds, colored sand/powder and different foil like papers. These are sold on nail art webshops and you can find them from normal stores too.
Then of course there are the nail stickers which are really fun to add after applying nail polish as they too bring something extra. I love adding some nail stickers to my nails if I just paint my nails one simple color. These can be found in many shops (at least here in Finland.)
They can look super cute. :)
I've now also started buying other decorations like the ones below. I bought these decorations from a normal crafts store and they are actually meant for decorating stuff like books, screens, boxes, etc. But they work really well as nail art!
*With any nail art decorations its important to add a top coat of see-through nail polish. ( I usually add 2 layers so it will properly protect the nails)
These were my tests this week: White contrasts really well with black and so does silver and gold so I really got my nails to stand out.