Congrats on the new tank.
I agree with aquakai about getting a few more of each of those a tetras. I group of more like 10 would look really cool.
Corys are super fun too, but there are also some other neat bottom feeders if you don't like corys like kuhli loaches, and porthole catfish for example.
For a centerpiece, there are some very pretty gourami species like the moonlight gourami or the snakeskin gourami.
Just a heads up, if the plecos are common plecos, they will get too big that the tank, so you may want to consider a different home for them if you can.