I recall ABC trying to emulate the early success of Sabrina by having 3/4s of the schedule (save for Boy Meets World) be made up of fantasy/supernatural shows for the 1997-98 season. They were You Wish, which was kind of a male version of I Dream of Jeanie and Teen Angel which had the extremely macabre premise for a TGIF show about a kid who dies after eating a contaminated hamburger and comes back to watch over his best friend and his family (w/ the mother played by Maureen "Marcia Brady" McCormick).

These shows lasted only one season (one of the biggest mistakes ABC made w/ their TGIF block in my humble opinion was making things too homogenized, like having Miller-Boyett produce all four sitcoms at the expense of something like Just the Ten of Us for example) and by this time, ABC somehow had difficulty replacing the aging Family Matters and Step by Step (which moved to CBS for their final seasons).

Every other show not named Boy Meets World or Sabrina in the original run of TGIF for some reason, lasted one season. They had Two of a Kind w/ the Olsen Twins, Brother's Keeper, which was pretty much a more family friendly variation of Two and a Half Men, and Odd Man Out (and other shows that I'm probably forgetting right now).

Unfortunately it's the way of the business to try to copy successful shows. You could argue that ABC was trying to copy Boy Meets World too, since a lot of the shows after it had a younger main cast with a teenage guy lead. I don't remember all the one season shows now in great detail, but I'm pretty sure I watched all of them at the time. I'm still surprised to this day that the Mary-Kate and Ashley show wasn't given a second season.

http://zvbxrpl.blogspot.com/2007/04/speaking-of-late-90s.html

I see that Sabrina the Teenage Witch Season 2 is getting released. As I've said before, this show was never again as good as it was in the first season, when Nell Scovell was running it. She left or was pushed out, several cast members were dropped by the new producers (including Paul "Freaks and Geeks" Feig), and it just wasn't quite the same. But it was still entertaining in the second season, and certainly it remained one of the more entertaining entries in the very difficult genre of fantasy-comedy.

How difficult it is to do fantasy-comedy was proved that very season (1997-8 (http://www.sitcomsonline.com/boards/showthread.php?t=286256)) when ABC made a decision that may have killed off its Friday night TGIF lineup: delighted with the success of Sabrina, they ordered two more shows that were fantasy-comedies in the exact same style. You Wish was from the underrated Michael Jacobs (creator of the underrated Boy Meets World), about a genie working for a single mom and her kids. And Teen Angel was from The Simpsons' Al Jean and Mike Reiss, about a kid who dies from eating a spoiled hamburger but comes back as the guardian angel of his geeky friend, who lives with his... yes, you guessed it... single mom. (Hilda and Zelda were so popular on Sabrina that the network apparently figured that people primarily wanted to see kids without father figures.) These producers weren't particularly happy to be doing this kind of material; Jean and Reiss admitted that they pitched Teen Angel only because ABC/Disney wouldn't take any of their other sitcom ideas. But the glut of wisecracking fantasy-comedies, of Sabrina followed by two inferior imitations, not only weakened Sabrina but weakened the once-mighty ABC family-friendly lineup.

I don't know what the situation was with Step by Step and Family Matters, whether or not there was a bidding war between ABC and CBS, or if ABC just didn't want them anymore. Whatever the reason, I think getting rid of those two shows was a huge mistake. If they had kept them for two more years, we would have been spared four mediocre one season shows.