Here are the fish from that site that I would consider suitable for that tank: Glowlight, honey gourami, betta (male/female), guppy, platy, swordtail, ram, cardinal tetra, neon, penguin tetra, amano shrimp, phantom tetra, panda cory, bumble bee goby, harlequin rasbora, white cloud (minnow cloud mountain), lampeye killie, kribensis, scissortail rasbora, diamond tetra, pristella tetra.
Now let's organize them.
list #1
Glowlight
cardinal tetra
neon tetra
penguin tetra
phantom tetra
harlequin rasbora
white cloud (referred to on there as minnow cloud mountain)
scissortail rasbora
diamond tetra
pristella tetra
list #2
honey gourami
female betta
male betta
guppy
platy
ram
lampeye killie
kribensis
swordtail
list #3
panda cory
amano shrimp
list#4
bumble bee goby
So... If you want a species tank pick any fish from list #2 or #4 and make a tank around them. You can breed them, watch them raise their young, enjoy a single species of fish doing what they do. Bumble bee gobies are on their own because they are brackish water fish. You will have to buy salt like is used in marine tanks and measure certain amounts to reach a saliinity between fresh and seawater.
If you want a community tank pick a fish from list #1 or the cories on list #2 (not both) and add 6-8 fish depending on size. Then pick a fish from list #2 and add 1 if it's the male betta or 2-3 of any of the others again depending on size. If you do not use cichlids (rams, kribensis) or labyrinth fish( gouramis, bettas) you could possibly add amano shrimp. If you really want shrimp with minimal risk to them leave out list #2.
These are my opinions on stocking based on 10 years of having tanks from 5g freshwater to 30g brackish to 20g marine to 90 fully planted freshwater with no filtration and years spent on the fishprofiles forum. Another good site is
http://www.aquahobby.com/e_freshwater_tropical_aquarium_fish.php . Put your fish name in the search bar in the corner and then select the correct one from the search. It will tell you size, recommended tank size (keep in mind this is for that fish only not a tank stocked with multiple fish), and comments from people about how well that fish gets along in various setups.