Nice! You can definitely just browse through each category to get a sense of which creators are on there, it's not a huge list. In the "Explore" screen, click on "Channels" first, then browse through the categories to see creators in each category. The "Latest activity" sort is also good to find active creators. For example: https://nebula.tv/explore/channels?category=gaming&sort=lastUpdated&order=desc
For videos, it might be worth filtering by "Original" and "Plus" if you're looking for higher quality content. Many of the channels have lot of older archived content, which is worth going through if you've found a creator you like. Though I mostly just check the "Everything" category for new videos to discover creators.
And of course their homepage is updated regularly with featured creators and categories.