Hi Baelyn. Welcome to the forums!
I'm afraid this forum may not be the best place to get an answer to your question, as this board is specifically about the AppGameKit. If you're looking to become a technical designer, I think AppGameKit's BASIC programming language would be a great place to start, as the skills you learn from using it will be widely applicable to other scripting languages you might need to use in the games industry. AppGameKit also has a VR plugin for the main desktop VR systems, so it could give you experience in that area too. There are other engines and frameworks out there of course, but as you're here, I'm assuming you're considering AppGameKit, and I can vouch for it being a very capable framework and a great starting point for learning game-dev, so long as you're willing to write code rather than using a drag and drop style interface.
What other tools would be useful really depends on what kind of a role you'd like to have in the games industry. If you'd like to be a gameplay programmer, learning C++ would be useful. Again that's something you can do with AppGameKit using "Tier 2", which allows you to call AppGameKit's functions directly from C++. If you'd like to be more involved in level design, learning some basic 3D modelling programs like 3DS Max/Maya/Blender might be useful.
I hope that's of some use. Feel free to ask if you have any follow ups or want to ask anything more specific.
