You may need something to edit textures with - most likely GIMP or Paint.net, if you’re on a budget - especially to prepare textures that you’ll use to build your particle systems and decals. Maybe something to handle sound mixing? I could suggest Audacity from top of my head, but take it with a grain of salt - sound mixing is not something I’m really familiar with. You’ll also need Visual Studio if you wish to dive into C++ programming (not needed for Blueprint). With those you can basically make any type of content.
Nothing else really comes to my mind. Good luck with your project 