General terms:
* Collection: This is a broad term that can encompass any group of works, including those with a common theme.
* Series: This term often implies a chronological order or a shared plot line, but it can also refer to works sharing a theme.
* Cycle: This suggests a recurring element or theme across the works.
More specific terms:
* Hexalogy: This term, while less common, specifically refers to a collection of six works.
* Sextet: This term is often used for a group of six poems or songs, but could be adapted to other genres.
* Thematic Anthology: This term highlights the common theme connecting the works.
Examples based on specific themes:
* Shakespearean Tragedies: A collection of 6 of Shakespeare's tragedies (Hamlet, Othello, Macbeth, etc.)
* Greek Myths Cycle: A collection of 6 Greek myths (like the story of Persephone, Heracles, etc.)
Ultimately, the best term to use depends on the specific context and the nature of the relationship between the six works.