The Centenary Catalogue says that Scott and his friend William Erskine edited this book together.  In the Advertisement the publishers (John Ballantyne & Co.) say:  “To one eminent individual, whose name they do not venture to particularize, they are indebted for most valuable assistance in selection, arrangement, and contribution; and to that individual they take this opportunity to present the humble tribute of their thanks, for a series of kindnesses, of which that now acknowledged is among the least.”  There is no critical apparatus.  The book contains original poems by Scott, Southey, Rogers, Joanna Baillie, and others not so well known.

  The Lady of the Lake.

Memoirs of the Duke of Sully.  Translated from the French [by Charlotte Lennox] ... a new edition ... corrected, with additional notes, some letters of Henry the Great, and a brief historical introduction embellished with portraits. 5 vols.  London.

Another edition, 4 vols.  London 1858, has these words on the title-page:  “A new edition, revised and corrected; with additional notes, and an historical introduction, attributed to Sir Walter Scott.”  I have found no external evidence that Scott was the editor.  The introduction sounds as if Scott wrote it, but that so much work could have been done by him without occasioning any record seems unlikely.  There is a historical introduction of 35 pp., and copious notes.  The book is one with which Scott was familiar.  See Memoirs of Robert Carey, pp. 34 and 41.

  The Poetical Works of Anna Seward, with extracts from her literary
  correspondence.  Edited by Walter Scott, Esq. 3 vols.  Edinburgh.

      The biographical preface is given in the Miscellaneous Prose
      Works.  The notes are by Miss Seward.

  Ancient British Drama, in three volumes.  London. (Printed for William
  Miller, by James Ballantyne & Co., Edinburgh.)

I find no evidence that Scott was the editor of this book, but it is sometimes ascribed to him in library catalogues.  It contains merely a two-page introduction and brief notes, and a collection of plays. (See above, p. 52, note.)

1811
  The Modern British Drama, in five volumes.  London. (Printed for
  William Miller, by James Ballantyne & Co., Edinburgh.)

      Vols.  I and II, Tragedies, with introduction in vol.  I.

      Vols.  III and IV, Comedies, with introduction in vol.  III.

      Vol.  V, Operas and Farces, with introduction.

These volumes apparently belong to the same collection as the Ancient British Drama, noted above, and the external evidence for Scott’s authorship is the same.  But the introductions are fuller, and they sound very much like Scott. (See above, p. 52, note.)

  The Vision of Don Roderick.

  Memoirs of the Court of Charles II, by Count Grammont.  With numerous
  additions and illustrations.  London. [Edited by Scott.]