I'm planning on using LÖVE(framework) for this jam and it's a code-based framework, so every community library is code. And these libraries handle stuff like object-oriented programming, collision detection, which are fundamental. Can I use these libraries or do I have to code it all from scratch? And is it possible to use stuff like Post Processing Stack, which has code in it?

Frameworks and engines, like LÖVE, are allowed!

The Post Processing Stack is a Unity-released package, therefore it's usage is allowed aswell!