The Life of Edward Lord Herbert of Cherbury, written by himself.  With a prefatory memoir.  Edinburgh; printed by James Ballantyne & Co. for John Ballantyne & Co. and John Murray. (A reprint of Walpole’s edition, with the prefatory memoir added.)

It is a question whether Scott edited this book, but it has been ascribed to him, and is given under his name without hesitation in the British Museum catalogue.  The prefatory memoir is short and largely made up of quotations, but it sounds as if Scott might have written it.  The book is one to which he often refers.  Mr. Sidney Lee, in his edition of the Autobiography, says merely, “Walpole’s edition was reprinted in 1770, 1809, and in 1826.”  Reprinted in the Universal Library:  Biography, vol.  I, London, 1853.

1809-15
  A Collection of Scarce and Valuable Tracts on the most interesting and
  entertaining subjects:  but chiefly such as relate to the history and
  constitution of these kingdoms.  Selected from an infinite number in
  print and manuscript, in the Royal, Cotton, Sion, and other public, as
  well as private, libraries; particularly that of the late Lord Somers. 
  The second edition, revised, augmented, and arranged by Walter Scott,
  Esq. 13 vols.  London.

There are some additions.  Scott says in the Advertisement:  “The Memoirs of the Wars in the Low Countries by the gallant Williams, and the very singular account of Ireland by Derrick, are the most curious of those now published for the first time....  The introductory remarks and notes have been added by the present Editor, at the expense of some time and labour.  It is needless to observe, that both have been expended upon a humble and unambitious, though not, it is hoped, an useless task.  The object of the introductions was to present such a short and summary view of the circumstances under which the Historical and Controversial Tracts were respectively written, as to prevent the necessity of referring to other works.  Such therefore, as refer to events of universal notoriety are but slightly and generally mentioned; such as concern less remarkable points of history are more fully explained.  The Notes are in general illustrative of obscure passages, or brief notices of authorities, whether corroborative or contradictory of the text.”  The following book contains a part of the same material: 

      The Image of Irelande with a Discoverie of Woodkarne.  By John
      Derricke, 1581.  With Notes by Sir Walter Scott.  Edited by John
      Small.  Edinburgh, 1883. (See Somers’ Tracts, Vol.  I.)

1810
  English Minstrelsy.  Being a selection of fugitive poetry from the best
  English authors, with some original pieces hitherto unpublished. 2
  vols.  Edinburgh.