The texts available in the 'other letter correspondences' section of
the Swedish Diachronic Corpus are listed below:

* King Gustaf III: Bref om Akademiens Inrättning	1786
* Sophie von Knorring:
  Bref till hemmet, under en sommarresa			1846
* Karl August Tavaststjerna:
  Korta bref från en lång bröllopsresa			1893	
* Pehr Wahlström:
  Bref till en vän under en Resa i Landsorterna		1800
* Härjedalsbrev						1531--1645


If you want to know more about the Swedish Diachronic Corpus, the
following SweClarin reports may be of interest: 

SCR-03-2019
Towards a Swedish diachronic corpus: Intended content, structure and format of version 1.0
Eva Pettersson & Lars Borin
url: https://sweclarin.se/sites/sweclarin.se/files/outline-swedish-corpus.pdf

SCR-02-2019
Swedish diachronic texts: Resources and user needs to consider in a Swedish diachronic corpus
Eva Pettersson & Lars Borin
url: https://sweclarin.se/sites/sweclarin.se/files/swedish-historical-texts_3.pdf

SCR-01-2019
Characteristics of diachronic and historical corpora: Features to consider in a Swedish diachronic corpus
Eva Pettersson & Lars Borin
url: https://sweclarin.se/sites/sweclarin.se/files/diachronic-corpora-sweclarin-v3.pdf