zsync2
Download only the changed bytes over plain HTTP.
interoperates with zsync
rdiff
rsync signature / delta / patch.
interoperates with librsync
zchunk
Content-defined chunked container + HTTP-Range delta.
interoperates with zchunk (Fedora/DNF)
vcdiff
VCDIFF (RFC 3284) delta encode/decode.
interoperates with xdelta3
bita
Differential file sync over HTTP (.cba archives).
interoperates with oll3/bita
Each tool is verified byte-for-byte against its reference implementation.