Martha Jones

No more than 3 Companion cards may be
on the battlefield at the same time.
{1}{w/u}: Martha Jones gets +1/+0 until
the end of turn.
When Martha Jones leaves the battlefield,
you may search your library for another
Companion card and put it in your hand.

I spent a lot of time with you, thinking I was
second best. But you know what? I am good!