A partial archive of sources and information related to BerkeleyDB maintained by a former employee of Sleepycat Software and Oracle's Berkeley DB team. This is not meant to be a comprehensive archive, as I have no plans to include anything related to releases under the GPL.
Releases from Oracle can be found at https://ftp.osuosl.org/pub/blfs/conglomeration/db/db-M.m.p.tar.gz as in 6.0.19
FreeBSD maintains a complete archive of releases as source code and patches they use.