One of the most important items of Old Norse literature is the so-called Poetic Edda, which is a collection of poetry whose earliest extant manuscript (the Codex Regius) was written down probably in the thirteenth century; the poems are all anonymous, although sometimes the Edda is called the Saemundar Edda, after the original attribution made by Bishop Brynjólfur, who happened to discover the manuscript. (Brynjólfur's attribution is generally rejected today.) The poems in the collection are older than the manuscript, of course, but in most cases we have no particular way of knowing how much older, although most of them are probably no earlier than the tenth century, and some probably much later than that. The exact set of poems included varies depending on the edition; the poems that are not in the Codex Regius are sometimes called the Eddica minora.
Another major item is the Völsunga saga, a prose account of the murder of Sigurð and the vengeance of his son Sigmund. The legends of the Volsung clan seem to have been extraordinarily popular; we have some poems about them in the Poetic Edda, but it is the Volsunga Saga that gives the most thorough and ingenious -- if not always perfectly successful -- unification of prior poetic traditions into a coherent prose narrative, and only the later, and German, Nibelungenlied has been a more influential account.
The Volsunga Saga seems to date from the thirteenth century, although the earliest extant manuscript is from the fourteenth or fifteenth century. That earliest manuscript collects the Volsunga Saga with another saga, the Ragnars saga Loðbrókar, the Saga of Ragnar Lothbrok, no doubt because it can be seen as a kind of sequel.
These three works, the Poetic Edda, the Saga of the Volsungs, and the Saga of Ragnar Lothbrok are the next fortnightly books. I will be reading them in the Hackett editions, translated by Jackson Crawford. His edition has all the poems in the Codex Regius manuscript except the Atlamal, and (like many others) adds some Eddica minora poems that are related in content and form: Baldrs draumar, Rigsthula, Voluspa en skamma, and Grottasongr. Crawford has a YouTube Channel in which he discusses topics relevant to Old Norse literature. If you are interested in the topic, his videos are all quite good. His introduction to the Poetic Edda, focusing on why it is important, how historical linguists reason out how old the poems must be, and its relation to Snorri's Prose Edda:
He also has videos on the Codex Regius itself. He also has extended commentary on the Volsunga Saga (Part I, Part II, Part III, Part IV, Part V, Part VI) and another video on the Saga of Ragnar Lothbrok.
We have touched on Volsung material in the fortnightly book before, with J.R.R. Tolkien's attempt to rework the story into an even greater unity, and we'll likely touch on it again at some later point if I ever do the Nibelungenlied, which seems likely enough given that I've been intending to get around to it for a few years now.