With the passing of Yaphet Kotto I was reminded of the talk that he was one of the front-runners to be cast as Picard for TNG and that he actually turned the part down before it went to Patrick Stewart (Kotto said he later regretted doing so, having become something of swelled-head and thinking TV was beneath him at the time)
I mention this because in looking up info for that I came across an article that has an image of a casting memo for the series and it's funny to see some of the names that pop up on it for the various characters including
Captain Picard
Stewart
Kotto
Mitch Ryan (who would later play Riker's dad)
Roy Thinnes (from Dark Shadows, Falcon Crest, and Airport 1975)
Patrick Bauchau (Belgian character actor with a long resume)
Cmdr Riker (spelled "Ryker" in the memo)
Jonathan Frakes
Michael O'Gorman (dude has all of 6 credits to his name, all guest appearances in TV series except for one small movie role)
Gregg Marx (soap actor and occasional guest spots on other TV shows like Doogie Howser)
Ben Murphy (late 60s/early 70s western actor who starred in Alias Smith and Jones before guesting in a whole whack of stuff afterwards)
Lt. Yar
Lianne Langland (played in a handful of TV movies. I remember her from a Perry Mason movie, but she also played Maureen O'Hara of all people in a movie about Lucille Ball and Desi Arnez)
Julia Nickson (long-time character actor. She did make an appearance on TNG as an ensign in "The Arsenal of Freedom")
Rosalind Chao (who would return as Keiko O'Brien)
Leah Ayers (was in Bloodsport and briefly replaced Maureen McCormick as Marcia Brady in a spinoff show about the kids grown up and older that tanked within 5 episodes)
Bunty Bailey (did some late 80s horror schlock but mostly was the girl in the video for A-Ha's "Take on Me")
Data
Mark Lindsay Chapman (he mostly worked a lot of soaps, 72 episodes of the 90s Swamp Thing series, the Langoliers TV mini-series, and had a role in Titanic)
Eric Menyuk (would later be cast as The Traveler)
Kevin Peter Hall (was the dude in the Predator suit for the first to Predator movies, as well as Harry in the Harry & the Hendersons TV series)
Kelvin Han Yee (long-running TV "that guy")
Lt. LaForge
LeVar Burton
Reggie Jackson (the baseball player?)
Tim Russ
Wesley Snipes

laugh

Victor Love (moderate character actor from the 80s onward)
Chip McCallister (IMDB lists a "Chip McAllister" who was in a Muhammad Ali biopic playing him at 18. that's pretty much the biggest thing he's got)
Clarence Gilyard Jr. (was the major supporting dude on Walker Texas Ranger and played the head tech nerd on Gruber's team in the first Die Hard)
Kevin Peter Hall
Dr. Crusher
Gates McFadden (listed as "Cheryl McFadden". And considered a longshot because of her stage commitments)
Anne Twomey (character actor who appeared in a bunch of dramas in the 90s and early 2000s)
Jenny Agutter (prolific English actress. Maybe best known now in nerd circles as the SHIELD head whose identity Black Widow takes during the infiltration in Captain America: The Winter Soldier. She was also a lead in Logan's run and currently stars in a long-running British show called "Call the Midwife")
Counselor Troi
Denise Crosby
Wesley Crusher
J.D. Roth (the host of Fun House, also voiced the title character in the 90s revival cartoon of Johnny Quest)
The notes below the list call Stewart and Bauchau the favorites for Picard, O'Gorman for Ryker (while being "atypical for the role"), and McFadden for Crusher (while questioning if her stage commitments might take her out of the running)
It also says Crosby is the only possibility for Troi (Marina Sirtis would be cast as the prototype Yar before she and Crosby would have their roles swapped) and Roth as the only candidate for Wes.
The odds-on favorites for Yar, Data, and LaForge are cited as Chao, Chapman, and Jackson respectively.
Imagine an alternate universe where Yaphet Kotto captains the enterprise with empathic counselor Denise Crosby, second in command "some guy that was in Miami Vice once", Chief O'Brien marrying someone else because his wife is the security chief, Dr. Crusher is English and her kid inexplicably isn't and also hosts a kids' game show, Data is The Traveler, and when they call down to engineering they get Mr. October.
Weird.