What To Add To A 55 Gallon Community Tank?

[Noobie]

Getting a new 55 gallon long tank and I am trying to decide what to add.

So far I have figured:

4 Corydoras (Corydoras trilineatus) (4 * 2.5" = 10")
12 Cardinal Tetras (12 * 1.5" = 18")
4 Oto Catfish (4 * 1.5" = 6")
4 Bumblebee Gobys (4 * 1.75"= 7")
Maybe some Bamboo Shrimp?

That leaves me with 14" of fish using the 1" per gallon rule.

What else would be nice to add to the tank? I would like something that is calmer and somewhat colorful. I enjoy the oddball type fish. The tank will be kept around 78 deg and be very well planted. It will have dark substrate with a river of white sand going threw the middle sectioned off by rock.

My 42 gallon tall tank consists of:

3 Veil Tail Angelfish
2 Silver Hatchetfish
2 Oto Catfish
2 Blue Rams
1 Gold Ram
1 Armored Catfish
1 Peacock Eel
1 Rubber Lip Pleco

Here are a couple pictures of my 42 gallon:

 

[Noobie]

 

[DevUK]

How about some pentazona barbs? They look cool and are supposed to be very peaceful community fish. I am going to be stocking a group of about 10 in my 47gal soon, but haven't had any yet so can't say from personal experience. But everything I've read suggests they are very good community fish