Shallan, Lightweaver

At the beginning of combat on your turn, draw a card then discard a card. When you do, you may exile it with a sketch counter on it.

{t}: Choose a creature card exiled with a sketch counter on it. Copy that card. You may cast the
copy. That copy costs {2} less to cast, and is a blue illusion in addition to its other colors and types.

When Shallan leaves the battlefield, sacrifice all illusions you control.