Doctor Who:Having to wait for a new season and a possible regeneration.
Sherlock:Season 3
Harry Potter:Each book AND Pottermore
Hunger Games:Catching Fire
The Mortal Instruments:The fandom who waited
Homestuck:every single update ever
TWEWY:WAITING 4-5 YEARS FOR A SEQUEL
Monsters Inc:11 Years for a sequel
Legend of Korra:Book 2
Kingdom Hearts:6 years waiting for KH3.
Golden Sun:7 years for book 3, no word on book 4.
Sly Cooper:7 years for a new game, only for it to be pushed back a couple more months.
Sam & Max:2 years and counting since the last season
Oswald the Lucky Rabbit:67 years between last cartoon and Epic Mickey
How to Train Your Dragon:TV show AND HTTYD 2
Left 4 Dead:Waiting for a third game.