Seven Deadly Sin Characters: Envy

Plenty of examples of envy between siblings.
Phillip's rivalry with his older brother was highlighted in an episode of Futurama.

Yancy Fry vs Phillip J Fry
Futurama
Eps:Luck of the Fryish


Eustace Bagge vs Horst Bagge
Courage the Cowardly Dog
Eps: Shirley the Medium
Eustace deeply resented his older brother's great success.(this episode is also an example of Eustace's greed. Only his greed could've driven him to contact his long-estranged late brother.

Second bananas are often very susceptible to this sin.One assassination away from the seat of power

Starscream vs Megatron
Transformers/Transformers:The Movie

Grand Vizier Iznogoud vs the Caliph
Iznogoud

Grand Vizier Jafar vs The Sultan
Aladdin

-other examples-
Richie Foley
Static Shock
Eps: Power Play
Static's best friend Richie feels a tinge of envy and finds himself making a shady deal with a man who can give him temporary superpowers.

Booster Gold
JLU
Eps:The Greatest Story Never Told
Booster Gold is a hero who craves the spot-light, and envies the attention given to the big heroes. He's given yet another low-key duty during a massive battle, but soon he must stop a world-ending threat that has escaped the JL's attention.


Straydog

In the episode "Beauty is Only Smurf Deep" after finding out from her magic mirror that Vanity is the fairest in the world, the pixie princess Periwinkle sets out to kill him. Fortunately, since the two of them share similar interests, they end up becoming good friends instead and the other Smurfs arrive just in time to save their friend.

Of course, Queen Grimhilde from Snow White and the Seven Dwarfs gets envious when she finds out that Snow White is the fairest in the land and seeks to kill her. Earlier on, Snow White is forced to do menial labor for her, but what really gets the Queen upset is the day a handsome unnamed prince shows up to sing to her about how much he loves her.

Lady Tremaine AKA the wicked stepmother from Disney's Cinderella is jealous of her stepdaughter's natural goodness and beauty--things her own daughters Drizella and Anastasia sorely lack. Cinderella is forced to be a kitchen maid for her stepfamily. Drizella and Anastasia don't behave any better towards Cinderella--although in the direct to video sequels, Anastasia does become a better person unlike her sister.

More than anything else, it's envy of Mister Incredible, and by extension, superpowers as a whole that drives Syndrome to develop the Omnidroid series of hero killer robots in Pixar's The Incredibles. Really, he's already got an elaborate underground base and toys galore to play with. No, Syndrome wants to prove himself to the supers of the world; nay, he wishes to surpass them. "And when everyone's super ... no one will be."

Alexandra Cabot wants what Josie's got: the hunky boyfriend and the successful pop-rock band. Many of Josie And The Pussycats' adventures were triggered by one of Alexandra's shenanigans to supplant Josie.

"Yogi's Gang" had an episode called "The Envy Brothers," in which the title villains made the animals envious of one another.

"Green With Jealousy," from the 80's iteration of "Teenage Mutant Ninja Turtles" had three of the turtles fighting over Irma after ingesting a love potion.

Also, in "Battle Of The Planets," Jason was more than a little envious of Mark, often trying to do things on his own.