Lost always played fast and loose with its timeline, but the introduction of the flashforwards – taking place three years after the "Oceanic Six" made their way back to civilization after months on the mysterious island – at the very end of Season 3 was a total gamechanger in the series. It will forever go down as one of the best time jumps in TV history.
Six Feet Under
Six Feet Under took "time jump" to a whole new level in their absolutely stellar and heartbreaking series finale, flashing forward repeatedly in time in the final episode to show each character's demise. A poignant and perfectly fitting end for a show centered on a family who runs a funeral home.
Who could ever forget Sydney suddenly waking up in Hong Kong in the closing moments of the Season 2 finale, with no knowledge of the past two years and having been thought missing during all that time? It changed everything.
The History channel series loves its time jumps, and there have been several. It's an effective way to show a lot of story and explore different times of Ragnar's reign. But I think the best and most iconic time jump was the very first one – Season 2 Episode 1 takes place in 796 AD but Episode 2 jumps ahead four years. Four peaceful years of Ragnar's reign has passed and terribly boring Aslaug has given birth to several more male children, after Lagertha refused Ragnar's offer to stay married and take Aslaug on as a second wife.
Season 6 of the long-running CW series picked up a full year after the events of Season 5. The fifth season's finale easily could have served as a series finale – with Sam, as a vessel for Lucifer, throwing himself into the cage to defeat him once and for all (OK, not quite, in retrospect, but he gave it a real go). Dean moved on and tried to live a normal life after that, without Sam and without hunting. When Sam returned from hell, the year's absence arguably changed their relationship forever.