none or maybe all depending on how full your glass is. In natural conditions every coral in the world would outgrow that tank. Corals are colonial, and will keep building until they run out of space or conditions change. So theoretically they will grow to the space available. You will have to trim them back to keep the tank looking cool but I wouldn't worry too much about size. Look for aquacultured corals as they are usually more hardy, and in a tank that small you will want hardy because small variations will affect the balance of chemicals and bioload substantially (there being less water to dilute with.) Aqua culutred corals also have the benefit of impacting reefs less.
Sympodium is a small polyped hardy coral, as are starburst polyps. Many kinds of Cloves and zoanthids would look cool and stay relatively small. If you are wanting to try hard corals, I would stick to montiporas. Good Luck!