A couple a days ago I decided to take a look at the archive of the Swedish Governor General of Bremen-Verden. It's preserved in Stade and parts of the catalogue is available through Arcinsys Niedersachsen.
I was quite unfamiliar with the this archive, but it turned out to be quite substantial as far as GNW correspondence is concerned. Many of the more prominent military and civilian officials from the first part of the war(Rehnskiöld, Liewen, Stenbock, Piper, Cederhielm etc.) are represented and the same is true for several of the most important diplomats (Lillieroth, Palmqvist, Cronström etc.). Notable are also some volumes concerning Governor General Gyllenstierna's march from Pomerania to Krakow in 1702. Other parts of Gyllenstierna's papers are preserved in the Swedish National Archives and in the Royal Library. At least parts of the "Swedish archive" in Stade have been microfilmed and these films are preserved in the Swedish National Archives.
The new archive building in Tartu has now opened, so it's time to restart my "excavations" in the Estonian part of archive of the Livonian Governor General. As I have noted before the level of service is excellent. Find the right volume in AIS and then just a few simple steps for ordering copies. I have by now acquired complete scans of about a hundred volumes and the (electronic) delivery of them usually only take a couple of weeks. The quality is always excellent and if there are any glitches they always fix them almost immediately. The price is very reasonable and unless the volumes are very thick (like the muster rolls for the period 1634-1694) it's entirely manageable. I have also made some forays into the archive of the Estonian Governor General (almost a dozen volumes thus far) and a couple of days ago I decided on a small experiment as far as the town council of Dorpat is concerned. There was in late 1691/early 1692 a most curious case concerning Harald Igelström, an officer and nobleman who killed two people and then managed to escape from jail and across the Düna to Courland. There is among the papers of the Livonian Governor General a lot of correspondence about the murders and Igelström's escape, but the letters do not contain any account of the circumstances. The case is mentioned in a few older works, but these versions appear to be incorrect. According to one of them it happened just before the war broke out in 1700 and that's obviously incorrect. Another preculiar detail is that Igelström was married to a daugther of Major Otto Wilhelm Klodt, who in 1702 was executed in Dorpat for treasonous actions during the Saxon invasion. The Igelström case was initially handled by the town authorities in Dorpat in January 1692.