I happen to be in Florida right now where coral stores are on every corner, so I figured it was a good time to branch out and justify a cost on vacation!Thats a nice looking setup! I started with a ten gallon desktop AIO when that was a new thing back in 2011. I put a Duncan in there and I still have it! I've moved 3 times since. So I would go with Duncans, frog spawns, maybe some zoas. If you're at a point where you get comfortable with your parameters you could do a Nem. I would avoid the urge to go SPS however if you do, maybe some stylophora as they are easy to care for but do need some light. You could also get away with some garden variety plating montipora if you have decent enough lighting. These are just a few things on my "hard to kill" list.