Displaying more than 10 labels in the list view is coming in Prodigy v1.4.0! See this thread:
In general, we'd still recommend using much smaller label sets – even if it means making multiple passes over the data. It's tempting to do everything at once, but annotation is often much more efficient and faster if your brain can focus on one or two categories at a time (instead of having to keep track of all the available options). Matt's comment here goes into some more details on this.