There are a lot of incredible wrasses that would look great. I like some of the different and less available clowns. I am not a big fan of the "designer" percs and occs, but have an incredible pair of Spotcinctus clowns!
I would STRONGLY suggest you not put a large puffer in a tank this size. Many puffers, including dog face and porcupine, get WAY too big. These puffers absolutely WILL outgrow that tank and will suffer if not moved to a much larger system. If you want a puffer, look at a valentini or saddle. Both are good options for a smaller tank. Just keep in mind that puffers have bone beaks for breaking shells and eating snails crabs and other inverts. They will almost certainly develop a taste for any and all CUC you may have or get.