Neon, Cardinal, Glow Light, Black Neon (glow light), green fire tetra (bloodfin)
I've got all these including an albino neon in tank with Goat and none of them bother him. Generally the albinos are fine with one exception.
If an "albino" of these looks kinda like a pristella/xray type in shape, they will behave differently.
Now I DO have pristella in tank with sherbert, but only pristella.
I have several glow lights that are now 35mm in length. You can also have 24karat tetras if they are 24karat tetras.
Just about any of the small tetra who are listed as shoaling fish will be fine. In my tank they all line up across the bottom in a ragged formation and swim in the current at night, leaving goat access to the top 3/4 of the tank. Be aware that what you see for sale in stores are FRY and not fully grown. Neons, Bloodfins and other long lived tetra can get very very big.
Neons and Cardinals seem to like 8 to 10, Glow Lights seem to be 6 to 9 (includes black neons) and the green fires you can get away with two to five of before they become a threat to territory.
I'd not have more than six small tetra without a secondary or larger filter nor would I have more than five pristella type without the same.
Do NOT fully load a tank until it is well established with plants and stable filtration.
If you put in some of these small tetra and they start hovering around the glass or the corners, they need more company of their own. Neons are very accepting and I'd suggest using three neons and two glow lights. The blacks seem to coexist with glow lights better than with neons.
A cardinal and a neon have slightly different body shapes and cardinals run the red line their whole bottom length.
You WILL get both sexes of fish, they scatter eggs so your betta will get live food from time to time.
Remember to treat each of these small fish as two inches right from the start, your betta is about two and a half inches.
You MUST have a fully established cycle before you add any fish other than a betta. If you don't you'll know within minutes because the tetra will all die. They're not only very sensitive to ammonia and nitrite but are also nitrite poisoned very easily. Special breeds like gold pristella are exceptionally sensitive.