Alright, so
despar anthias- online and in my books I am seeing a minimum tank size of 55 gallons. Also, they really like to be kept in groups or at least a pair. Otherwise, they are prone to disease and don't feed well. I am not sure that this is the best choice for your 30 gallon. I would choose something else with the same color or body shape that can be housed in a smaller tank.
bangaii cardinals- This is a good choice for a 30 gallons. Keep only 1 or a pair. I have heard that keeping them in odd numbers is bad because in small spaces, they pair up and kill the odd one out. You could keep 4, but that is going to take up all of your stock room.
tomato clown- you could do one of these, they do get quite large for a 30 gallon. Clownfish have a tendency to get territorial and in a small tank, You may have some issues. I am not 100% but it may be safer to go with the percs instead, and they you could have a pair.
dottyback- you could go for the magenta, or the fridmani. These fish are known as semi aggressive but you should have no issue if you pick one and don't add any others. Otherwise they would kill each other. Also, no fish that are similiar shaped either. These little guys can get really crazy if they feel threatened. Also related with similiar behavior, but cheaper and more easily attained, are the royal gramma. With a half purple, half golden yellow body, these guy have great color and personality. I have had mine forever and he is really a hardy little bugger. I have read that they are jumpers and have known people to have theirs jump out of open top tanks, but mine is in a shallow tank now with an open top and he is fine. He has never tried to jump and I have never seen him near the top of the tank.