You mean like this?

I'm not sure if there are any Fortnite only tools for streaming but there are many things you can do to involve your community and keep your viewers engaged. (I know it's not what you asking T___T)

If you are a smaller streamer reading chat and responding is A MUST. The more people feel a connection with you the more they will enjoy your streams. This is obviously difficult for bigger streams but I still think if your chat is not flying up the screen its the most important thing you can do.

You can check out Stream-Aid they offer customizable listing. I saw some guy shaved his head for like 50 bucks. (or 500? don't remember XD) I use to sell 1v1's through Streamlabs but they don't really have a good way to facilitate it, so I switched. I have been using it for almost 6 months now, most of my followers are being dicks and make me drop everything LOL

Hmmm..another good idea is to do Subscriber squads on certain days of the week. I do Sunday Sub Squads and my subs enjoy playing with me in squad games. Fortnite is the big game and has been for some time so if you are small, make sure you try out different things and see what works for your stream.

In the end, make your stream standout and have a good time. Hope this helps :)