Obviously, you can grow these all at once if you choose to, but if you mean a true sea of green where you grow a number of small similar plants next to one another to create a level canopy designed to maximize yields, that probably isn't going to work so well here.
Since you've got who knows how many strains there, you can only expect that the plants will have different structures, growth rates, heights, and flowering times. If its even possible at all, getting these all into one level canopy is likely to be difficult and labor-intensive. If your idea is to try and grow small individual plants, the genetics may make that tough. . .some of these may just be stretchy and won't want to stay short.
You didn't mention where the bags in question came from or what was in them, but as another consideration, if these are bag se-eds from domestic commercial grows, its likely that many (or even all) were created by accidental pollenization from hermaphroditic pollen.
The plus there, is that most of the beans will be "feminized" and you will probably not get many (or even any) true males. Thats good, but assuming its true, the downside is that bagseed from hermie parents is itself more likely than usual to create hermie plants. If that happens and you miss even one of them (say because you're busy dealing with 19 other unknowns at once), you could end up with a seed-ed room.
I don't know how much space you have, let alone experience or time to devote to this, but trying to grow out literally 20 different unknown strains at once is a bit of a "job". Unknown strains require more attention than usual, and 20 of them at once. . .that's a lot of extra work if you want any chance of maximizing the potential of each plant. My suggestion is to try and limit the "total unknowns" to only a few per grow. That way you'll have a much easier time identifying problem plants, excellent plants, training them, getting nutes dialled in, perhaps cloning the best of them, and you won't end up with a "jungle".
Assuming there is other stuff you have that you might want to grow at the same time, personally IIWY, I'd just run a few of these at a time (EG 4-6) in numerical order.