Classic cartoon and comic strip rivals/adversaries

Source: joke-battles.fandom.com

• Archie vs. Reggie
• Batman vs. Joker, Penguin, Riddler, Catwoman, and other villains
• Buck Rogers vs. Killer Kane
• Bugs Bunny vs. Daffy Duck
• Bugs Bunny vs. Elmer Fudd

Source: independent.co.uk

• Bugs Bunny vs. Yosemite Sam
• Dagwood vs. Mr. Dithers
• Dexter vs. Susan “Mandark” Astronomanov
• Dilbert vs. Pointy-haired Boss
• Dudley Do-Right vs. Snidely Whiplash
• Fred Flintstone vs. Mr. Slate
• George Jetson vs. Mr. Spacely

Source: villains.fandom.com

• George of the Jungle vs. Lyle Van de Groot
• Homer Simpson vs. Mr. Burns
• Inspector Gadget vs. Dr. Claw
• Jerry vs. Tom

tomandjerry.fandom.com

• Jimmy Neutron vs. Professor Finbarr Calamitous
• Jonny Quest vs. Dr. Zin and other villains
• Mighty Mouse vs. Oil Can Harry
• Penelope Pitstop vs. Sylvester Sneekly (the Hooded Claw)
• Pink Panther vs. The Inspector
• Pink Panther vs. The Little Man

Source: deviantart.com

• Pixie/Dixie vs. Mr. Jinks
• Popeye vs. Bluto
• Roadrunner vs. Wile E. Coyote

Source: vox.com

• Rocky/Bullwinkle vs. Boris/Natasha
• Roger Ramjet vs. Noodles Romanoff
• Smurfs vs. Gargamel
• Snoopy vs. The Red Baron
• Spiderman vs. numerous villains
• SpongeBob Squarepants vs. Plankton

Source: youtube.com

• Spy vs. Spy (see image at top of post)
• Superman vs. Lex Luther and numerous other villains
• Tennessee Tuxedo vs. Stanley Livingston
• Tommy Pickles vs. Angelica Pickles

Source: quotetv.com

• Tom Slick vs. Baron Otto Matic
• Top Cat vs. Officer Dribble
• Tweety Bird vs. Sylvester the Cat

Source: aminoapps.com

• Underdog vs. Riff Raff
• Underdog vs. Simon Bar Sinister
• Wally Gator vs. Mr. Twiddle
• Woody Woodpecker vs. Buzz Buzzard
• Yogi Bear vs. Ranger Smith

Source: pinterest.com

SOURCES:

• Personal knowledge
• https://en.wikipedia.org/wiki/Lists_of_animated_television_series
• https://en.wikipedia.org/wiki/List_of_newspaper_comic_strips