Chia Network now provides official database checkpoint downloads as torrent:
https://www.chia.net/downloads/#database-checkpoint
We strongly recommend using the official download!
Historically, since before there was an official Chia Network-provided download, our team-member Gnomuz has provided an automatic backup of the blockchain database running around midnight CET every day, and it's then uploaded to Dropbox. This download is also still available and updated daily:
https://www.dropbox.com/s/iijtnyj26lc9pbo/blockchain_v2_mainnet.sqlite.bz2?dl=0
The .bz2 snapshot can be decompressed with 7zip on windows (minimum version 21.07), lbzip2 recommended under Linux.