This Blender add-on is designed for bulk downloading of assets (Free and Full) from BlenderKit.com in ".blend" format. Main reason for its existence is that the Official add-on requires you to manually enter the link and save the project file for each asset.

UI is located in Sidebar (toggle by N key), in [BK Downloader] tab :

Links file – text file containing list of links (one per line) to each desired resource

Output path – folder where the downloaded ".blend" files will be saved

API Key – downloading assets released under Full plan requires a paid subscription.

Delay – delay in seconds before starting download of new asset after the previous one has finished downloading (additional random 1–5 seconds will be added to it for each asset).

Console – displays a list of assets to download, their order numbers, names, and current downloading status. When finished, you'll see a report on successful/failed downloads.

SPOILER: Where can I get API Key?

After payment go to the ADD-ON tab of your profile (Upper right corner of website -> Your round avatar -> ADD-ON) and press Show API Key. Paste this into add-on "API Key" field and you will be able to download Full plan assets as well. For security reasons, the add-on does not store the entered value in memory – you need to specify it for each session.
Don't share your API Key with anyone, otherwise you may get banned. If you suspect that your API Key has leaked, click [Reset] in the ADD-ON tab on website to create a new version and delete the old one.

SPOILER: Is this legal?

Assets downloading are performed via their open API. Links to each asset can only be obtained from their official website. Downloading assets from Full plan without an API key (paid subscription) is not possible with this add-on, nor is downloading Private assets (hidden by the author) possible. So, using this add-on is completely legal and cannot lead to ban, as long as you don't download hundreds of assets with 0.1 second delay in 24/7, of course.

SPOILER: How to install?

Just like any other add-on for Blender:
1) Upper left corner of Blender
2) Edit
3) Preferences...
4) Upper right corner of the opened window
5) [↓]
6) Install from disk...
7) Select the downloaded .ZIP file.
The add-on is activated automatically.

Tested in Blender 4.2.6 LTS. If you have any suggestions for improving the add-on or bug reports, please write in this thread.