Imaginary Friend Glove

Wondrous item, Rare, Requires attunement

Cloaked companion. While you grapple a creature by holding its empty hand (or equivalent appendage), it is invisible. If that creature attacks or casts a spell, this property is lost until you complete a long rest.

Just your imagination. Willing invisible creatures of your choice within 30 ft of you can be seen by you, and don't make sound when they move.