So, barring spells like a wish being available to a PC, there are no spells or magic that allow the PC to just pull a rabit out of their hat, as in create a brand new effect never before seen in the game, in the scope of a gaming session.

You disqualify your own statement with self only view again. So it all means TO YOU.
D&D however CAN and DOES allow the PC to combine effects.
Someone previously suggested trapping the BBEG in a stone and locking it away. All these things can be done with magic.
Many spells have effects of others built into them. 3rd specifically, I think, lets you combine spells without creating new ones by using more than one at the same time for a combined effect.
You don't need a wish to "pull rabbits out of your hat". You just need a Heward's Handy Hassenpfeffer Hat.
I only take vegetables raw, the rest you can have raw all to yourself and far away from me!
But by RAW, read the DMG...any of them. tell me how your RAW holds up to the DM being told essentially:
Here's some rules, don't always follow them.
