Here I have:
A group of textures created by members of the Planet-MoFo team.
Many of them are designed for use on a sphere map object, or an arc of 360 degrees. A usage example is provided below, with rotation matrix.
A group of small and simple textures designed with transparency in mind. I hope to have some similar but more complex textures soon. 

Some images we did not create, but have modified. These are royalty-free and unrestricted usage. A source link is provided. 
An enhanced night-time earth image obtained from this site.  http://antwrp.gsfc.nasa.gov/apod
A political world map obtained from this site.  http://www.cia.gov/cia/download.html
An orange peel texture obtained from this site.  http://www.sxc.hu/browse.phtml?f=view&id=445684



# texture on sphere
textureMatrix 
  name spheretrix 
  spin 0
  shift .1 0
  center .5 .5
end 
material
	name spheremat
	addtexture http://trepan.bzflag.bz/planets/earth.png 
	color 1 1 1 1
	texmat spheretrix
end
sphere 
  name planet
  divisions 18
  position 0 0 75
  size 20 20 20 
  radius 20
  specular 0.5 0.5 0.5
  shininess 64
  rotation 0
  smoothbounce
  matref spheremat
  texsize 1 1 1 .5
end


# texture on ring
textureMatrix 
  name ringtrix
  spin 0
  shift .1 0
  center .5 .5
end 

material
	name ringmat
        addtexture title.png
	color 1 1 1 1
	texmat ringtrix
	dyncol -1
	notexalpha
end

arc
  name bzflagring
  divisions 48
  angle 360
  ratio .1 # (outrad - inrad) / outrad
  position 0 0 71.5
  specular 0.5 0.5 0.5
  shininess 64
  size 30 30 9
  rotation 0
  smoothbounce
  matref ringmat
  texsize 4 1 1 .5
end
License for a-delusion_seawaterfull2.png: Public Domain