Jesse Kornblum is a computer forensics researcher and engineer. You can read more about him in his [Wikipedia entry] or his official web site http://jessekornblum.com/
md5deep - Cross platform recursive hashing program. Computes MD5, SHA-1, SHA-256, Tiger and Whirlpool hashes. Can also match against sets of known hashes.
foremost - File carving program
ssdeep - Usually called Fuzzy Hashing, this program implements Context Triggered Piecewise Hashing.
FRED - The First Responder's Evidence Disk