yogi bear and boo boo
quick draw mcgraw and baba louie
tom and jerry
syvester and tweety
fred flintstone and barney rubble

Rocky & Bullwinkel
Hekyll and Jekyll
Dastardly and Muttley
Go-Go Gophers
Boris and Natasha

The Fox & the Crow
Chip 'n' Dale
Spike & Tyke
Beany & Cecil
Ruff & Reddy
The King & Odie
Hokey Wolf & Ding-a-ling
Lippy Lion & Hardy Har Har
Augie Doggie & Doggie Daddy
Snooper & Blabber
Tennessee Tuxedo & Chumley the Walrus
Secret Squirrel & Morocco Mole
Ricochet Rabbit & Droop-a-long Coyote
MushMouse & Punkin Puss
Peter Potamus & So-So
Breezly & Sneezly
Peabody & Sherman

dick dastardly and muttley
mr peebles and magilla gorilla
cow and chicken
dexter and dee dee- dexter's lab
dynomutt and blue falcon
pixie and dixie

Spiffy and Fleabag
Shaggy and Scooby
Batman and Robin
Inspector Gadget and Penny
Pebbles and Bamm-Bamm

Here's one that goes all the way back to the silent era:

Mutt and Jeff (based on Bud Fisher's long-running comic strip)

Fred and Barney

Ranma & Akane (small pic, Ranma in his GIRL form with Akane)

Garfield and Odie
Goofy and Donald
Ren and Stimpy
Beavis and Butt-Head

Garfield and Odie
Goofy and Donald
Ren and Stimpy
Beavis and Butt-Head
Goofy is thought of more as Mickey's sidekick than Donald's (Having replaced Horace Horsecollar in the role, around 1935 or so)

I can't recall ever seeing Donald and Goofy together, in any venue. Mickey,
Donald and Goofy worked as a trio in several animated cartoons; and Mickey
and Goofy were a team regularly in nearly all the Mickey Mouse comic
books.

Tom & Jerry was great