I think most of them are some kind of angel wing begonias. See how they look like pairs of wings on a stalk? I don't know what the big leaf one is.

I don't know, but I love them all together! Never thought of planting them that way.

The Begonia forum has been very helpful for me in the past

Here is a link that might be useful: Begonia forum

I didn't really plan on grouping so many different begonias in one pot, I'd planted one type in a good size pot but it never really filled out so I took cuttings from other begonias that I'd rooted in water and just added them to the existing pot. I really like how it turned out even though I hadn't realized how big it'd gotten until I went to move it inside!

Here's what someone over on the begonia forum said.

"I would say that the canes in the middle are all mallet begonias. The lightest green looks like Don Miller, the one with the dark green broader stripes looks like Miniperba and the pink might be Maurice Amey."

I think that the Miniperba id might be right but I'm not sure about the Don Miller or Maurice Amey judging from the pictures I found online.

Another place to look is American Begonia Society. Sort the table by category and look through the "Cane" begonia images.

Here is a link that might be useful: Begonia Images