The micro rasboras I mentioned and the R. uropthalmoides will all work. The R. uropthalmoides has a little color.
The order of color would likely be
Boraras Brigittae males have deep red when spawning but usually it is the dominant male and a secondary which have the darkest color.
The Phoenix or Merah has some less deep color but orange red in males and Strawberry /Naevus this one has a bit of pink
In Rachel's list she has the others too.
For the Boraras Brigittae, I have bought fish 12 in 2020 and 2021 and in 2020they just all died in 2021 and all but 2 died. These were very small fish. like fry. and delicate after the travels to the fish store and me.
There is a store much farther away and their fish are usually a little bigger, they get them in almost every week and so their fish have some time to grow.
Instead of $3. they are $6 at the farther away store. But they seem stronger, so next time I try to get some it will be from the other place.
The Chilis really do have some males which are so dark. They love a subdued light and some botanicals /leaves in the tank as do shrimp.
Also some Red Root Floaters are nice as they add seclusion and shady spots which the fish also like. I have kept a different variety of these guys together as well.
They live around 2 years or a little more with the others. Chilis seem not to live as long as some of the other individuals at least in my tanks.
They can live in a eco type tank replicating a natural environment, all the way to a Iwagumi. I love to see Iwagumi tanks but I keep more jungle type and biotope style tanks because I think the fish are happier.
For the 30G, one of my favorite fish for the upper 1/4 of the tank is the Microdevario Kubotai Neon Green Rasbora also really are amazing fish periwinkle to lavender top and yellow green bottom half.