Within moments of his reveal, Reiji Akaba has been christened by many as "Hipster Kaiba", especially when he wears that trendy hoodie while eavesdropping in episode 9. Just take one look at him and no further explanation is needed.
Yuya has been nicknamed "Tomato Head" by many. Once again, such a name needs no explanation.
Yuya being sad, uncomfortable or upset. Wilting/rotting tomato.
The Dark Duelist Yuto is also referred to as the Goth Duelist, Edgeplant or Dark Yuya.
Can you imagine that Ayunote Satomi Akesaka is Esdeath?
Teasing Creator: The showrunners seem to know exactly what will annoy the fans and lampshade or address it. Examples include:
Yuya's Ass Pull of getting his Pendulum Monsters mid-duel is considered as such in-universe.
Futoshi, who is considered The Scrappy by many, and is a wee bit of a Fat Idiot, usually gets a few derogatory comments thrown his way. Special mention goes to when he's being the Load and crying, to which Yuzu (albiet gently) tells him not to cry.
Your Size May Vary: In episode 24, Hidekazu Ebina (the episode's animation director) said that he intentionally made Yuto taller than Yuzu despite that he's supposed to be shorter than her. His reason was that this was supposed to give Yuto's exposition a sense of seriousness.