For many playtest cards, you’ll need to make a generous assumption that basic game rules would be updated to allow them to work. The Mystery Booster 2 Playtest Card Notes section (reproduced here in individual Gatherer rulings) provides guidance for fitting these cards into the existing rules structure.

Tokens created with A Girl and Her Dogs’s first ability are still subject to the “legend rule”, so be wary of giving two Dogs the same name or naming a Dog after an existing legendary Magic card.

Playtest cards aren’t legal for play in any tournament format other than Mystery Booster Limited formats. On the other hand, we expect they will spice up a wide variety of non-tournament games (as long as everyone’s on the same page about using them!).

Playtest cards use a modified version of game symbols, such as and . These modified symbols should be treated as the standard symbols during play.

You may give the Dog any name, including the name of an existing Magic card. Good names for Dogs include, but are not limited to: Booster, Bryn, Comet, Jasper, Killer, Pax, Pi, Ranger, Rocket, Sgt. Pepper, and Isamaru, Hound of Konda. (We thought you might need some suggestions to get you started.)