TLtools is a collection of high-quality libraries made by Taehl:

TEsound	A sound manager that makes it easy to use sound and music
TLbind	A simple system for creating professional control schemes
TLfres	Lets games run at any resolution, easily and without stretching
TLpath	Add A* pathfinding to games
Tserial	Converts tables into strings and back. Good for saving games, multiplayer, etc.

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TLibCompress

Can zip and unzip strings, reducing their size. A good way to save bandwidth when sending strings across a network.

TLibCompress.CompressLZW(string) returns a zipped string
TLibCompress.DecompressLZW(string) returns an unzipped version of a zipped string