First of all, we can define a "staple" to be a card that is played in, and benefits, the grand majority of existing decks in the current metagame.
These choices are all of my own opinion, you are free to agree or disagree at your discretion =)
Carryover Staples from before September 1st:
- Cold Wave: Locks down spells and traps for two whole turns. "Cold Wave + Black Rose Dragon" and "Cold Wave + X-Saber push for game" are common destructive plays. Only backrow dependant decks can't take advantage of this great card.
- Giant Trunade: A generic OTK enabler. What more needs to be said?
- Pot of Duality: This card is so good. I can't say it's good enough to justify the price tag on the secondary market, but it's still really damn good. It raises the consistency factor of inconsistent decks, like anti-meta based strategies, for example. Being able to see 3 cards off the top of your deck, and from there pick the one that best helps your current board setup is amazing. This card was widely sought after and played upon release so I'm lumping it in the pre-September 1st category.
- Solemn Judgment: God says No! Royal Decree is rising in popularity, but fact of the matter is, this is the best trap card in the game.
- Book of Moon: Arguably one of the best, if not THE best, -1 in the game.
- Gorz the Emissary of Darkness: Amazing card, it has the power to turn games around.
- Stardust Dragon: The best synchro monster in the game. If you were to invest in only one synchro monster, this would be it.
New Staples as of September 1st:
- Monster Reborn: Newly limited, there's a reason this card was banned for so many formats. The only deck that's unable to take advantage of this card is Gravekeepers.
- Dark Hole: Also newly limited, another card that was rightly banned for many formats. No matter what deck you run, you play Dark Hole, it's as simple as that.
Cards I no longer deem to be staples this format:
- Heavy Storm: Banned..... =(
- Brain Control: Banned!!!! =)
- Mystical Space Typhoon: With everyone setting backrows like crazy, singular backrow destruction has become far less effective.
Cards I consider to be semi staples this format:
- Bottomless Trap Hole/Mirror Force/Torrential Tribute : These traps do what they've always done, destroy stuff you don't want to see. Though as mentioned, Royal Decree is rising in popularity, not very many decks can take advantage of it; those that cannot stick to the generic trap lineup.
- Solemn Warning: Unless you're playing Royal Decrees, you're going to want to play Solemn Warning. If played right, this card is amazing. This card, unlike Pot of Duality, needed a bit of time after its release before it gained widespread popularity.
- Cyber Dragon: Baits out Solemn Warnings and Bottomless Trap Holes without eating up your normal summon for the turn. Gladiator Beasts and Machina Gadgets hate this card.
- Effect Veiler: I'm listing this as a semi staple instead of a staple because currently it's sided more than mained, and even then it isn't maxed out. The one card that can save you from a Cold Wave + Black Rose Dragon play, and wrecks decks that are heavily dependant on their monster effects.
- Certain generic synchro monsters (Brionac Dragon of the Ice Barrier, Ally of Justice Catastor, Black Rose Dragon, Scrap Dragon, Goyo Guardian) : Not 100% essential like Stardust Dragon is, yet amazing enough that I cannot leave them unmentioned. Brionac and Black Rose are borderline staples IMO.
- Ryko, Lightsworn Hunter: If your deck can take advantage of milling, and you want something that can target and destroy ANY card on the field, than this ferocious yet adorable canine is for you! Just watch out for attacking XX-Saber Darksouls! (or Sangan)
- Seven Tools of the Bandit: An increase in trap usage due to the banning of Heavy Storm means Seven Tools of the Bandit can put in work. It's better than Trap Stun in my opinion since it's a counter trap. Side/main at least one copy, depending on your deck and personal preference. Disregard this last statement if you're playing Formula Monarchs / Shooting Star Fish or if you main Royal Decrees.
- Sangan: Declining in popularity due to the increased popularity of Thunder King Raioh, BW- Shura, Flamvell Firedog, and XX-Saber Fulhelmknight. It's tough to be a small monster this format. Nonetheless the ability to search your deck for any one of a variety of monsters, without discrimination towards attribute or type, cannot be underestimated. Sangan can still find a home in Absolute Zero, Quickdraw Plants, and some X-Saber builds.
- Glow Up Bulb: A pseudo-Plaguespreader Zombie. A self-reviving tuner with no significant downside. Excellent balanced card. Because it's currently really new, it's difficult to gauge exactly how popular this card will be, hence I chose to list it as a semi-staple for now. It's restriction effect prevents you from running more than one copy though.
That's all for today, thanks for reading. Leave any comments you may have below ~