Gold Mine:
Copyright <BµmM>
CC-BY-SA license

LearnToPlay:
Copyright Tridemy & Cøke
CC-BY-SA license

Sunny Side Up:
Copyright Ravie
CC-BY-SA license, grass_main is redrawn from original Teeworlds grass_main mapres (Apache 2.0 license)

Tsunami:
Copyright louis
CC-BY-SA license

Tutorial:
Copyright unique2 & Alisa
CC-BY-SA license