u/Sarlax

Augustus has for more than twenty years been gathering power for himself and expanding the empire. As the sun sets on the city and he enjoys his meal, a bright star appears in the dark eastern sky and rapidly grows large as it catches the last light of the setting sun. Augustus and other Romans only have a moment to marvel at the light before it explodes into the city with the force of the Tunguska Blast.

What happens to the known world in the aftermath of Rome's destruction? Do the provinces get ruled by post-roman military dictators or do they overthrow their conquerors?

What happens to the messianic Judaic cults? Assuming the OTL historicity of Jesus (not to mention the Star itself), does Jesus rise to greater prominence as some kind of post-Roman prophet, or is he overshadowed/made irrelevant by the death of Rome?

What are some interesting options for messing with spell slots? How can you exploit them?

Items like Pearls of Power recover a previously-prepared and cast spell, but like most items they become exponentially more expensive for higher spells. Rings of Wizardry double your slots of a particular level but are very expensive.

Staves allow you to store 1 slot per day and you can "launder" those slots in the sense your staff can cast spells you otherwise couldn't. Critically, you don't pay material component costs for staff slots, but you must first spend 50 x the normal material cost when crafting the staff. And if you have something like Leadership to recruit Adepts or if your GM is liberal with Spellcasting services, you could order/pay NPCs to charge your staves for you. Wands effectively convert cash to slots.

Some class features and feats mess with spell slots. Arcanists can turn slots into reservoir points (but not vice versa). Faith magic allows a wizard to prepare a divine spell using a higher-level arcane slot; Split Slot divides 1 slot into 2 lower slots. Echoing Spell enables you to cast the same spell twice in one day.

Mnemonic Enhancer is a spell that allows you to prepare more lower spells; Mage’s Lucubration is like a Pearl of Power in that you can instantly re-prepare a recently-cast spell. Today's spell Alchemical Allocation duplicates a potion right after its use.

What other notable options exist for messing with spell slots like this?