Plates, they normally have food on them although some people like to hang commemorative ones on their walls. It's a simple concave design with the purpose of keeping the food together in one place, making it easy to eat. A lip or rim keeps sauce in place rather than running everywhere. The plate has been in use for centuries with much success.
Most plates are circular but there has been a trend over more recently for square or oblong ones. These were initially found in certain restaurants but are available for civilian use these days. These days places serving on non circular plates have moved on.
A clog, frying basket, even a dog bowl have been used to serve food recently. I feel the rise of the gastro pub and hipster chic have led to this. Gimmicky to say the least serving food on anything that comes to hand has led to bit of a backlash with a We Want Plates campaign. You can see plenty of examples at @WeWantPlates of the weird and wonderful examples of things used to serve food these days. There is a downside to using unconventional serving dishes:
