Here´s some online resources and links I have collected over the years.
The links are Cinema 4D and general computer graphics stuff.
IOR values
http://vray.info/topics/t0077.asp
Cinema 4D general stuff
Free Simbiont Darktree shaders
http://www.darksim.com/html/downloads.html
C4D Download – Various Cinema 4D stuff: scenes, shaders, libs etc.
http://www.c4ddownload.com/
Blueprints
http://www.the-blueprints.com/
Car blueprints (clear blueprints of car models)
http://www.smcars.net/forums/blueprints-archive/
Textures
Lighting
HDR Labs with free HDRI panoramas and sIBL stuff
Free Stock photos
http://www.dreamstime.com/free-photos
Tutorials
c4dcafe
c4d cafe cinema 4d tutorials/
Digital Tutors
Beginner tutorials for Cinema 4D
Greyscalegorilla
Greyscalegorilla´s Cinema 4D tutorials
C4DTraining
http://www.c4dtraining.com/
Lester Banks Cinema 4D tutorials
http://lesterbanks.com/cinema-4d-tutorials/
Various tutorials, Max, Maya, Cinema 4D
CGTerminal
http://cgterminal.com/category/cg-tutorials/
Character modeling tutorials
Antropus character modeling tutorials
Mathematical tutorials for Cinema 4D
http://www.3d-meier.de/
CINEMA 4D & BODYPAINT TUTORIALS
3D Kiwi´s Bodypaint tutorials – commercial
http://www.c4dcafe.com/bpshop/
Cinema 4D and game modeling tutorials by Psionic. (Old but still very useful.)
http://www.psionicgames.com/?page_id=46
Cinema 4D plugins / plugin developers
Lumen, ZBlur, Cineview, Edgeshader and Enhance C4D.
http://www.biomekk.com
Tools 4D.
White Lights. Giga shader etc.
http://www.tools4d.com/
Kyroyumes
Interposer, Greebler etc.
http://www.kuroyumes-developmentzone.com/
Scripting and coding in Cinema 4D
XPRESSO
PYTHON
Some interesting finnish production companies, 3d and animation sites
Pinata (works)
http://www.pinata.fi/work.html
Twisted Films
www.twistedfilms.fi
Radiant Graphics
Iron Sky – makers of Iron Sky nazi parody
http://www.ironsky.net/
User sites
Jani Karvonen
http://www.janikarvonen.com/
Mikko Aaltonen
http://mikkoaaltonen.org/