McGonagall
Creatures: Revival

Minerva is one of the most powerful starting Witches because she is a two-for-one where both of her abilities are extremely useful. Starting with Minerva denies your opponents this incredible two-for-one, gives you constant access to one escape-from-Adventure-free card, and allows you access to one of the best lesson types in the game at no additional deckbuilding cost. Transfiguration is a powerful Lesson type, and has some of the best universal control and action advantage cards in the game. McGonagall is your emergency button to get through popular Adventures like Escaping the Dursleys, Pep Talk or Riding the Centaur when you have no other option. Try to only use McGonagall to escape an Adventure if you are going to win that turn. If your opponent can get you to use McGonagall's ability early, they know you will be stuck for sure under their next Adventure.

Peeves is possibly one of the best non-starting Character cards in the HPTCG. His uses are almost too many to name, but mainly Peeves serves as a way to both disrupt your opponent and refill your hand. Peeves is an excellent response to popular hand control strategies (especially Escaping the Dursleys) and provides a great way to keep your tempo up by refilling your hand. Peeves also shines as a pseudo-burn spell, dealing your opponent an additional 7 "damage" without using an action. Peeves is so strong in so many decks that your opponent may play one down before you.
In the absence of Ginny, Peeves becomes that much more important. He is going to be the primary way that you refill your hand when you start to run out of gas. Try to balance refilling your own resources with denying your opponent a chance to benefit off Peeves themselves.

Hagrid Needs Help is the perfect Adventure for this deck and is a great Turn 1 play against any deck. Your opponent will always have 1 fewer Action even when they solve Hagrid Needs Help immediately, which they will be forced to do or fall way behind. When they solve Hagrid Needs Help, he does a minimum of 8 damage but will often do 11 if your opponent decides to draw the 3 cards from the reward. Giving your opponent extra cards at the same time as reducing the amount of things they can do is a nice way to mitigate the benefit of them solving this card, making it feel a lot like a win-win for you and a lose-lose for them. Followed by a second Hagrid Needs Help, you'll often find your opponent down a third of their deck before the game even really gets started. The burn done by this Adventure is great value for two actions, and the fact that they are reduced to one action means that they aren't going to be responding with an Adventure of their own which means you are relatively safe on the following turn.

Sandstone Gargoyle is the bread and butter of your creature damage in this deck. Thanks to McGonagall's extra lesson, there's only two Lessons standing between you and playing these Gargoyles. They are by far the best bang for your buck against non-creature decks, and even against other creature decks you will often be able to get these down before they have creatures forcing them to either start playing them early or to take early damage. Damage from these adds up fast, dropping two at a time on turn two is an incredibly strong opening for this deck. Follow a Hagrid Needs Help opening with two Lessons on turn two and drop two Gargoyles on turn three and your opponent will already have your boot on their throat. An easy way for your opponent to make these gargoyles much less effective is to just drop a creature, but remember a well-timed Dobby's Disappearance or Picking on Neville can move your opponent's creatures out of the way long enough for Steelclaw to do serious work.

Marble Gargoyle is Sandstone Gargoyle's bigger brother, being a bit larger, costing a bit more, and dealing much more damage. Use the same strategies to deal maximum damage with Steelclaw as the little Gargoyles - bouncing enemy creatures, preventing your opponent from playing cards, or playing Steelclaw the same turn you drop them.

Black Bat just barely misses the cut in the Classic version of this deck, but with all of the extra space we get he is absolutely the first addition to the deck. Black Bat mitigates the top drawback of Creatures which is the fact that most of them do not do anything proactive the turn they are played. Black Bat deals two damage on his way in, promising at least minimal returns on your investment. It's also less enticing for your opponent to remove without actually killing or discarding it because of its ability. Outside of the extra two damage, Black Bat pressure will add up quickly over time.

Slinking Ferret is in this list to help pad the card advantage in a list that is missing the consistent draw power that Ginny Weasley provides. Ferret ekes it out over popular tutor cards like Desk Into Pig because even one damage each turn is better than sinking one action into spending a second one (playing the creature.) Slinking Ferret is a fancy version of using an action to draw a card because it provides long-term value as well as provides a bump to your Steelclaw numbers. I teeter back and forth between cutting Ferret for more pixies or potentially Baby Acromantula who solves a similar problem with having enough live cards in hand.

This is a little bit of a cheeky add, but I have to admit I love the type of effects that cards like Cornish Pixie provide. Cornish Pixie is in here namely to cripple a combo deck or to galaxy brain your opponent and steal their next play when they put themselves into a predictable situation. The more game knowledge you have, the better Cornish Pixie becomes, with an incredibly high ceiling and a decently high floor as well. Cornish Pixie is almost always going to give your opponent a hard time unless they are sitting on an answer, but forcing them to choose between getting their own strategy back or disrupting yours is the kind of bad choice that you want to be giving your opponent as you keep the pressure up on them.

Welsh Green Dragon is the finisher and the big payoff card in this deck. When your opponents are trying to slow you down or build towards their own strategy, you'll be chipping away at them with Gargoyles as you build up to cash in on a big Welsh Green Dragon turn. Welsh Green does you the massive favor of dealing his damage to your opponent's face as soon as he hits the table, and Welsh Green Dragon followed by Steelclaw is the explosive game-ending play you're looking for while you're navigating your opponent's Adventures. Sculpting a hand around Welsh Green Dragon, Platform 9 3/4, and multiple Steelclaw is what you're looking for before using Professor McGonagall to break out of an Adventure to win the game.

Hedwig is here to help you get important pieces out of the discard pile, which ends up being almost exclusively Steelclaw or an Adventure, with the occasional Welsh Green Dragon. Hedwig is a nice piece of consistency in a deck that doesn't have a lot of ways to search for or reuse pieces.

Steelclaw is your primary damage dealing card and is used in conjunction with your creatures to do lethal damage extremely quickly. In any game that doesn't end through attrition, Steelclaw is going to be what gets you there. Holding two Steelclaw in your hand feels like pocket aces, and following a Welsh Green Dragon with Steelclaw is a staggering amount of damage. Steelclaw helps you convert otherwise slow cards into immediate threats and lets you hit your opponent with Creatures by circumventing their largest weakness, the delay between them coming into play and having an effect. Don't waste Steelclaw early unless you're about to Peeves, as it is by far the most damaging card in your deck. It's your #1 target for Hedwig as well as the card you want to plan your Platform 9 3/4 turns around. Being an aggro deck, McGonagall Creatures is always racing to keep tempo up. A midgame Steelclaw isn't a bad idea if you feel the tempo slipping in your opponent's favor.

Ah, good ol’ Dobby’s Disappearance. This is another card that could have an entire article dedicated to how ridiculous it is, and I’m really not sure what the thought process was as they were designing it. In my opinion, Dobby’s Disappearance is the best card in the HPTCG by a landslide. Dobby’s Disappearance basically allows you to undo one (or two!) of your opponent’s actions for free, as it replaces the action that you use to cast the card. Dobby’s Disappearance works on any permanent, most importantly able to return Adventures and Characters to the opponents hand for even more action advantage over them.
Following the B&R list for Revival play, Dobby's is restricted to 1x copy in a deck making the timing on when you play Dobby's Disappearance much more important. Hedwig being able to rescue your 1 copy is going to go a long way here.

Let's be honest, Picking on Neville is in here to try and pick up Dobby's scraps. With the restriction on Dobby's Disappearance, we turn to the other 4-cost control option in Transfiguration. While not providing nearly as much of an action advantage and not allowing as many lines of play during your turn, Picking on Neville does a good job of keeping your opponent from building up too fast as your creatures snowball your advantage turn by turn. Picking on Neville is often just going to be a piece of removal early, but combined with another Picking on Neville or your 1x Dobby's Disappearance you can sometimes get some really good information out of your opponent by seeing what they choose just to make their choice moot anyway as you force them into a bad position.

Actions are the most important resource that you have in the Harry Potter Trading Card Game. Platform allows you to turn early lesson investments into an extra action later in the game, and is one of the best answers to cards like Hagrid Needs Help, Pep Talk or Locked In that are trying to control the number and type of cards you can play next turn. Most importantly, Platform allows you to play multiple Steelclaw on the same turn as a big threat like Marble Gargoyle or Welsh Green Dragon. After ramping up to a Welsh Green Dragon and playing it, it will leave you with 5 power which is just enough to activate Platform 9 3/4 once and have both the power and actions remaining for a double-Steelclaw. Platform also gives you the ability to play a Character or Adventure alongside a creature (Hedwig into an Adventure or Character is a good example).

Just a quick note on the Lessons. I write up these lists without including or planning them around sideboards. In the Heir of Slytherin set they have printed cards that shut down the abilities of starting characters including the Lessons that they provide. I think that main-decking a sufficient amount of Transfiguration Lessons can mitigate the effects of those cards against this deck almost entirely, and if I was playing with a sideboard I would probably include more Transfiguration Lessons in the sideboard and play an even smaller amount in the main deck. You really only ever need a Transfiguration Lesson in those situations, but in those situations it is your only (albeit a very simple) out.