This is the first such post I've done so apologies in advance if I format the thread incorrectly.

I've left out some of the other language variants. I cases where he's listed for the series as a whole and for individual discs I went with the latter as it's not unknown (though rare) for an actor to change names mid-series

William Callaway 54 titles (132 profiles)
Bill Callaway 46 titles (57 profiles) - some overlap with the above; will edit out as they are found
Listed in the IMDB as William.

The Challenge of the Super Friends sets under William Callaway cover the same Super Friends season as the ones under Bill Callaway so one has to be wrong; unfortunately my set went missing years ago.

William Callaway:
"CHiPs" - The Complete Third Season
Annie Hall (confirmed by TiM)
Cartouche
Challenge of the Super Friends
Defenders of the Earth: The Complete 65 Episode Series (all one season) (confirmed by me from bonus episode in Flash Gordon set)
DuckTales season 1 (confirmed by Gamemaster)
Flush
Fun With Dick and Jane (confirmed by TiM)
G.I. Joe: Season 1 - Part 2
G.I. Joe: The Movie
Gomer Pyle, U.S.M.C.: Season 5 aka Final Season
Hulken - Uhyret Vender Tilbage
Inhumanoids: The Evil That Lies Within: Animated
Inhumanoids: Vol 3 & 4
My Little Pony and Friends
Scooby-Doo Meets the Boo Brothers
The Smurfs: 'Tis The Season To Be Smurfy
The Smurfs: Complete Season 1
The Smurfs: Holiday Celebration
The Smurfs: Music Collection
The Smurfs: Smurfette
The Smurfs: The Smurfic Games
Taxi: The Complete Second Season: Disc One (confirmed by me)
Yogi's Great Escape

Bill Callaway:
Challenge of the Super Friends
Darkwing Duck: Volume 1: Disc 3: Episodes 19-27
Drak Pack: The Complete Series (one season)
Galtar and the Golden Lance (confirmed by me via Saturday Morning Cartoons 1980s)
G.I. Joe: Season 2 (Part 1)
The Great Northfield Minnesota Raid
Help! It's the Hair Bear Bunch (confirmed by me via Saturday Morning Cartoons 1970s: Volume 2)
The Incredible Hulk: Complete Series Box Set - 1982 (confirmed by me)
Love American Style: Season 1
Pac-Man: The Complete Second Season
Pro Stars: Slam Dunking with the Airman
The Richie Rich - Scooby-Doo Show - Volume One
Ruby-Spears Superman: Disc 2: DC Comics Classic Collection (Superman) (confirmed by me)
Scooby-Doo! Winter WonderDog
Sealab 2020: The Complete Series (confirmed by me via Saturday Morning Cartoons 1970s: Volume 2)
The Smurfs: 'Tis The Season To Be Smurfy
The Smurfs: Complete Season 1: Disc 3
The Smurfs: Holiday Celebration
Super Friends! A Dangerous Fate (confirmed by me; this is season 5 of Super Friends)
Super Friends! Legacy of Super Powers (confirmed by me; this is season 6 of Super Friends)
Super Friends: Volume Two (confirmed by me)
That Girl: Season Two
Thursday's Game
The Wild Wild West: Season 3: Disc 4
The World's Greatest Super Friends!: And Justice for All: DC Comics Classic Collection (confirmed by me; this is season 4 of Super Friends)

For TV credits: a season, not a disc, counts as one title. Other than that:

'Annie Hall': William Callaway

'Fun With Dick and Jane': William Callaway

'The Great Northfield Minnesota Raid': Bill Callaway as Calliopist

'Thursday's Game':  Bill Callaway as Cabbie