This focus can be in the form of any class focus you wish and can be used to cast any spell you know, regardless of class. Though it will take a hand to use. This is a +2 focus.

The Magic Must Stand You have +4 on all concentration checks.

Font of Magic You know one extra cantrip while attuned to this focus, the cantrip can be from any spell list.You can change what cantrip this is at the end of a long rest.

Emergency Cast Once per long rest, when you are out of spell slots of a given level, you can cast one more spell at that level at the cost of a lower level spell slot.

Notes: A spellcaster