The Leftovers, Source: HBO.

Time Warner's (TWX) HBO will bid adieu to some of its top shows in the next year -- a situation shared with competitor AMC of AMC Networks (AMCX -0.60%). But looking beyond the return of highly lauded newer series True Detective, some interesting projects are waiting in HBO's wings on the development slate. The end of June brings a sci-fi drama from the creator of Lost. Filming has begun on a J.K. Rowling project. And Ryan Murphy looks to have another show join his successful series roster.

HBO's hit shows ending soon include vampire drama True Blood and Boardwalk Empire, which follow on the heels of last year's end of Treme. AMC finds itself in a similar position after losing Breaking Bad to its finale last year and long-running hit Mad Men approaching its finish. But while both channels have existing hits continuing to air, HBO has some buzz-worthy projects waiting that could further boost the channel's return to dominance.

What projects should HBO fans keep an eye on?  

Leftovers from the creator of Lost 
Scheduled to premiere June 29, The Leftovers focuses on those left behind in a small town after a global Rapture. Stars include Justin Theroux, Christopher Eccleston, and Liv Tyler -- some recognizable names, though none is really a major audience draw. But it's the development team of Lost co-creator Damon Lindelof and Tom Perrotta -- the writer of critically acclaimed film Little Children and the novel that's the basis for the series -- that makes The Leftovers one to watch.

Lindelof has spent most of his post-Lost career focusing on developing films that include the hits Star Trek: Into Darkness and World War Z. But Lindelof remains best known for his Lost association and that show's large, devoted following could tune in to give The Leftovers a chance. 

J.K. Rowling's The Casual Vacancy 
Author J.K. Rowling followed her record-breaking Harry Potter book series with a sharp swerve into local politics with the adult-geared novel The Casual Vacancy, which will now receive the miniseries treatment from HBO in partnership with the BBC. Last week, Michael Gambon -- also known as the second Professor Dumbledore in the Potter film series -- was cast in the project. 

According to The Guardian, the book Casual Vacancy has sold over 6 million copies worldwide since its release two years ago. That's an impressive sales statistic, though it understandably falls far short of the dizzying heights reached by the Potter series. But will the popularity of Rowling's first foray away from children's books prove a ratings success for HBO?

Transitions from younger audiences to adult ones don't always go smoothly even with a popular author. Stephenie Meyer's first Twilight film brought in nearly $400 million on a $37 million budget. But the film version of her adult-oriented movie The Host only brought in $63 million on a $40 million budget. Rowling fans could similarly turn away from Vacancy. (And put down the pitchforks, fandoms. I'm only comparing the two authors in terms of cinematic potential, not in terms of quality.)

Ryan Murphy gets Open  
Glee and American Horror Story creator Ryan Murphy received a pilot order for Open, which Deadline described as "a modern, provocative exploration of human sexuality and relationships." The cast includes Thor's Jaimie Alexander, The Hunger Games' Wes Bentley, and Anna Torv from Fringe. 

Murphy had prior success with somewhat controversial sexual material with American Horror Story and Nip/Tuck, both of which aired on 21 Century Fox's (FOX) cable network FX. Glee originally had a bit of sexual innuendo for a teen-oriented show on Fox, but that was dialed down after the first season in favor of a greater focus on continuous singing. But Murphy also suffered a failure last year when same-sex dads sitcom The New Normal was canceled by NBC after one season.

Open could fare much better than Normal with HBO as a home. The channel has found success with a number of sex-oriented shows that include Hung, Californication, and True Blood. And HBO and Ryan Murphy have an established relationship following the AIDS-focused television movie The Normal Heart.

Where HBO stands now
Time Warner reported first-quarter results in April and HBO alone accounted for nearly 18% of the company's overall revenue so the channel remains a top priority. The strongest performers in that quarter were the fourth season opener of Game of Thrones, which attracted 17 million viewers, and the new series True Detective with a per-episode average of about 12 million viewers. 

Foolish final thoughts 
HBO's riding high with the successes of Game of Thrones and True Detective. But the upcoming ends of popular shows mean that new projects need to stream in -- and these three projects seem likely to strike a chord with audiences.