Parallax Sounds is a pack that aims to change EVERY sound in Minecraft with something more realistic. Zombies are more terrifying, portals are creepy and mysterious, weather is beautiful and destructive, animals sound like animals.
PvP Sound Pack changes the sounds in Minecraft to be better for PvP. The sounds in this pack make each action and each kill more satisfying
Sounds of Tamriel is a pack that aims to change sounds in Minecraft with sounds similar the The Elder Scrolls Skyrim for a more Nordic and medieval feeling. This works with addons, texture packs, shaders, and even on servers. It changes hundreds of sounds
It is a pack that changes the color and shape of tools to be more realistic; diamonds are now a whitish blue instead of a greenish blue, shapes are slightly tweaked to be more life like.