The two shows that come to mind are:

Full House-Those Better Not Be The Days (The kids take advantage of the guys who have a daydream about the future as it relates to the way the girls were taking advantage of them).


Facts of Life-Golden Oldies (The girls and Beverly Ann imagine themselves older and living in the same house.



Any others?

The Facts Of Life: In “Dream Marriage” Blair receives a marriage proposal and she dreams of what her life might be like in the future, in the year 2000.

Season 5, episode 20 (February 22, 1984)

Growing Pains-=Maggie's Dream= Chrissy becomes a teenager in Maggie's dream, which is influenced by her fear of being an older parent in a sea of youngsters taking their kids to preschool.

Boy Meets World= Seven the Hard Way (2)-=Mr. Feeny tries to help the group reconcile after their prank war goes to far; Eric has a glimpse into what with happen if they all go their separate ways.

Good Luck Charlie=Futuredrama=A future Charlie looks for advice from Teddy's video diaries to resolve an issue when a future Toby gives Charlie the silent treatment.

Shelley Longs final episode of CHEERS showed Sam and Diane in the future in one scene.

Cheers - I don't remember the episode title but it's one from the Rebecca years. It had to do with Frasier's will, which had been made the same time that Sam had the results to see if he was able to get someone pregnant. The final scene flashes to the future with an old version of Lilith, just after Frasier has passed and it's revealed that his will and Sam's results got mixed. Oh, and Sam WAS able to get women pregnant. ;)

Family Matters - I believe the episode was titled "Old and Alone." It's where Laura falls asleep and then dreams she's an old lady (and like the title implies) is alone.

That '70s Show - In the season premiere of the fourth season, an angel shows Eric what his life would have been like if he had never dated Donna. This includes going to the future... the '80s!

This wasn't limited to sitcoms, so let's not forget Dark Shadows' brief foray into the future (1995, I think). When Julia and Barnabas arrived Collinwood was a wreck.