Where can Charm move a unit? Is it limited to the unit's possible standard moves (e.g., does the unit need flanking to move between battlefields)?

Ruling: Charm can move a unit to either battlefield or the unit's own base, regardless of the unit's normal movement restrictions like flanking. Standard move restrictions only apply when exhausting units to move them.

Nuances:

• You cannot move units to other players' bases or invalid locations like the trash
• External effects that prevent moving to/from certain locations still apply (e.g., Vilemaw's Lair prevents moving units back to base from there)
• Charm can move exhausted units since exhausting is only a cost for standard moves
• Whether you can legally play Charm targeting a unit at Vilemaw's Lair with destination being base is uncertain and not definitively resolved