This pack contains files from the next web-sites, together with saved versions of original web pages:
http://www.nleymann.de/games/darkstone/dsIndex.html
https://darkstone.it-taucher.at/en/index.html

Archive from nleymann.de contains selected campaigns and tools (backup and game editor).
Archive from darkstone.it-taucher contains the same campaigns, 40+ mini-campaigns and scenarios, text walkthroughs for some of them and QuestEditor with tutorial.

I checked all of the files with Kaspersky Antivirus (it found nothing) and excluded from this pack some exe-files (like "money trainer") from the sites that looked suspicious for Chrome browser and Yandex Disc.

Download link (for the sake of safety, don't forget to re-check it with anti-virus if you can):
https://disk.yandex.by/d/eM1u2qgDjdnYZw

All of the custom campaigns are placed in "...\Steam\steamapps\common\Darkstone\Quest".
If you will look at the folder in Steam version of DarkStone, you will see there is already one file in there - "Journey In Uma.mtf" (it's an official additional campaign by Delphine Software).

"MFT" is an extension for DarkStone quests, and you need to place the ".mft"-files from this pack at the same folder as "Journey In Uma.mtf" to play the additional campaigns.

In original Steam version campaign in-game list looks like that:


If everything went fine, you will see this in campaigns in-game list (left screenshot represents "nleymann.de" archive, right screenshot represents "darkstone.it-taucher" archive):

New or never-seen quests for DarkStone are rare nowadays, so they may have a high value for the fans. If you have one, you can post a link to it in the comment section, and I will include it in this list.

1) Four Magic Rings! Enhanced! (by vivienne; 2007)
First public release date: 2020.
See the comment section for more information.

Original link:
https://drive.google.com/file/d/1ZOkGs8cpqXc4lu7TZZNZ0lbHZJXo0_Lh/view?usp=sharing

Mirrors (in RAR archive):
https://disk.yandex.by/d/3-hrjkV1LikJOw