Almost any plant are good for fish. As far as spawning, Im not sure. I would imagine any type of moss like java, willow, xmas and so on. However, I do know that java is one of the few mosses that like warmer temperatures as the betta does. Willow and xmas prefer cooler. BUT! I have both in my betta tank and all is flourishing! I also imagine that grasses are good. I have some dwarf grass and it would be excellant for fry! My shrimplets love all my plants. Nerites are a good snail to compliment the tank. I personally like assassin snails because everytime I recieve a mail order of plants they come with hitchhikers (unwanted snails), and my assassins eat them for me
. Apple snails are very big and very dirty. They are beautiful though!
Hope this helps!