I want to not only create a part in a 3d game that confuses people completely, I also want to try these in other unity engine games.
What do you mean by “exploits”? Like bugs that can be taken advantage of to make the game behave in non-intended ways?
These are usually not so much bugs in the physics engine, but things like badly placed scene collision geometry, loopholes in game logic/progression, input system, etc. There’s also developers making incorrect use of the physics engine as well, but that’s not an issue with the engine in and of itself. So different games will have different “exploits”, even if they’re all made with Unity.
Unity uses PhysX as its physics engine, by default. It can also optionally use Havok, and there’s integrations for other engines like Bullet. Both PhysX and Havok have been used for many years in hundreds of games, both indie and AAA, and are also used by many game engines other than Unity. By this I mean that both are battle-hardened, you’d be hard pressed to find any actual “beneficial” bugs in either physics engine that are common to all games that use them. It’s far, far more likely you will find bugs specific to the game, caused by its developers, regardless of the engine(s) they use.
Exploits and bugs in general are, by definition, non-intentional. The moment they’re there for a reason they become a feature (an obscure one, but still put in there on purpose).