Dickon Tarly
Time of death: Episode five, "Eastwatch."
Cause of death: Dickon, like his father, refuses to surrender and bend the knee to Daenerys Targaryen. Daenerys has Drogon burn him alive.
Randyll Tarly
Time of death: Episode five, "Eastwatch."
Cause of death: Randyll refuses to surrender and bend the knee to Daenerys Targaryen, despite his fluctuating loyalties and having seen the wrath of Drogon. Daenerys has Drogon burn him alive.
An unknown, but large number of Lannister soldiers
Time of death: Episode four, "The Spoils of War."
Cause of death: Drogon breathes fire on the Lannister army, turning them into ash that blows away.
Eventually: Ellaria Sand
Time of death: Unknown.
Cause of death: While we don't see Ellaria die on screen, actress Indira Varma confirmed to Entertainment Weekly that this was her last appearance on the show. She'll have a slow death rotting in the dungeons of the Red Keep, but fortunately we won't see it.
Olenna Tyrell
Time of death: Episode three, "The Queen's Justice."
Cause of death: Cersei wants to give Olenna a cruel death in King's Landing, but Jaime convinces her otherwise, and he gives Olenna poison. But Olenna goes down memorably. Right after she drinks the poison, she confesses to Jaime that she was the one who poisoned Joffrey, and she wants Cersei to know it.
Tyene Sand
Time of death: Episode three, "The Queen's Justice" (kind of).
Cause of death: Cersei locks Ellaria up in a dungeon with her daughter, Tyene, who she poisons the same way Ellaria poisoned Myrcella: with a kiss and a poison called "The Long Farewell." So Ellaria has to watch her own daughter die a brutal death, and there's nothing she can do about it.