Here’s an amazing topic that includes a lot of plugins.
A program that I recommend is blender. For a beginner, it may be a bit hard to work around, as the UI interface and keys are slightly complicated, however there’s a large amount of tutorials that help with navigating within the software. Blender allows for so much more outside of Studio, but be wary of the triangular/part count when importing into Studio. Blender essentially allows you to create assests that can be exported into Studio, as well as vice verca. Hopefully this helps 
Blender Guru, creates awesome tutorials about Blender; you can find that here. I also recommend Grant Abbit’s tutorials, which can be found here. ↓↓
Also remember, no one starts out perfect. Practise makes progress.