cdb is a fast, simple way of storing large constant databases. It maps string keys to string values.
Sample JPEG image with Exif metadata and the output of exiv2 on the image
ngrep is a pcap-aware tool that will allow you to specify extended regular or hexadecimal expressions to match against data payloads of packets. It currently recognizes IPv4/6, TCP, UDP, ICMPv4/6, IGMP and Raw across Ethernet, PPP, SLIP, FDDI, Token Ring and null interfaces, and understands BPF filter logic in the same fashion as more common packet sniffing tools, such as tcpdump and snoop.
Libnet is a high-level API (toolkit) allowing the application programmer to construct and inject network packets.
http://packetstormsecurity.org/UNIX/libnet/
GNU libavl is the most complete, well-documented collection of binary search tree and balanced tree library routines anywhere.
Defraggler can defragment entire hard drives or individual files.
Recuva is a free program that recovers files deleted from your Windows computer, Recycle Bin, digital camera card, and MP3 player.