This list was posted over at Unix-Ninja. I take no credit for these. Posting these here for my own convenience.
Extract md5 hashes
# egrep -oE '(^|[^a-fA-F0-9])[a-fA-F0-9]{32}([^a-fA-F0-9]|$)' *.txt | egrep -o '[a-fA-F0-9]{32}' > md5-hashes.txt
# egrep -oE '(^|[^a-fA-F0-9])[a-fA-F0-9]{32}([^a-fA-F0-9]|$)' *.txt | egrep -o '[a-fA-F0-9]{32}' > md5-hashes.txt