dnd regain spell slots
Can I use Spell Mastery, Expert Divination, and Mind Spike ...
You regain all expended Pact Magic spell slots when you finish a short or long rest.
Rod of the Pact Keeper DnD 5e - Warlocks Power
You regain all expended spell slots when you finish a long rest. For example, if you know the 1st-level spell Cure Wounds and have a 1st-level and a 2nd-level spell slot available, you can cast Cure Wounds using either slot.
Paladin Spells - D&D 5th Edition
Character optimization guide for the DnD 5e Paladin's spell list.