RTFC
Once per turn: You can Tribute 1 monster; Special Summon 1 "Zefra" monster from your Deck.
Zefraath
This is only banned monster that can attack twice
Number 95: Galaxy-eyes Dark Matter Dragon
You know this monster for its role with Souleating Oviraptor (2 answers accepted)
Petiteranadon/Babycerasaurus
Printed in the Lost Millennium as an awful Pot of Greed, this spell card saw extensive use in the anime from Yugi to Mai and even Marik
Card of Sanctity
Machina Gearframe
1 Machine monster
This is the only forbidden spirit monster
Yata-Garasu
During the End Phase, if a Fusion Monster(s) was sent to your GY this turn: Add this card from the GY to your hand.
Incredible Ecclesia, the Virtuous
This card forms the win condition of a gimmicky OTK deck from goat format
Armed Samurai - Ben Kei
This card sees play with Infernoble and Mecha Phantom Beast Auroradon to recycle Mecha Phantom Beast Coltwing.
Underworld Fighter Balmung
Although better known in the TCG for its ability to Special Summon itself, in the anime, this card was known for letting Jaden draw 2 cards if it was the only monster he had.
Elemental HERO Bubbleman
Spirit of the Six Samurai
It's not a boulder, it's a rock
Amano-Iwato
Gains 500 ATK/DEF for each Winged Beast monster you control, except this card.
Raidraptor - Force Strix
This synchro monster sees some play in swordsoul as a giant beater that gets stronger if it wins combat
Draco Berserker of the Tenyi
This card can revive monsters on destruction, but it's probably better known for sniping cards out of the extra deck
True King Lithosagym, the Disaster
In this anime, this card's damage boosting effect only applied against level 5 or higher monsters
Odd-eyes Pendulum Dragon
Y - Dragon Head
X - Head Cannon
This is one of the most competitively successful spirit monsters, most recently seen in early versions of Tri-Brigade Lyrilusc
Kinka-byo
When this card is destroyed by battle and sent to the Graveyard: You can Special Summon 1 "Fire King" monster from your Deck, except "__________________"
Fire King High Avatar Garunix
Fossil Warrior Skull Knight
Featured in an old Farfa video about cheating, this field spell highlights the inherent problem with confirming the contents of a player's hand when resolving certain effects
Kozmotown
A well-known searcher from 5ds, this spell card, in the anime, had a wider variety of monsters it could add in addition to a better effect to load the graveyard.
Tuning
Pitch-Dark Dragon
Dark Blade
One of only 2 spirit monsters whose names actually contain the word "spirit," this one is a walking board wipe
Dark Dust Spirit
Once per your turn, when a Spell/Trap Card, or its effect, is activated (Quick Effect): You can negate the activation.
D/D/D Flame High King Genghis
Rex Raptor used this dragon monster in Waking the Dragons
Tyrant Dragon
This card received some hype with the release of Summon Sorceress to potentially lock your opponent out of playing monsters
Ido, the Supreme Magical Force
Known in older formats for boosting ATK and removing cards from your opponent's GY, in the anime, this xyz monster was able to remove entire card types.
Number 80: Rhapsody in Berserk
Doitsu
Soitsu
This card has the highest level of all spirit monsters
Amaterasu