What are available arguments for wp_oembed_get?

The whole idea of embedding is that you do not have control over how the embedded content is being styled and it is controlled by the server from which the content is embedded. The embedding server might allow some control over the embedded content via the URL parameters but to know how to achieve that you will have to consult the documentation of the provider.

You can enclose the embedded content in a div with whatever class you want, but that unlikely to help you much.