A collection of a wide area of specific PDF's. Most are tutorials or in depth explanations of a given topic. I'll try list article subjects as I can. If you have a useful article, please leave a comment with a link to it.

http://advances.realtimerendering.com/s2010/index.html

Covers the following topics -

Caustics Mapping: An Image-space Technique for Real-time Caustics

http://graphics.cs.ucf.edu/caustics/

http://www.csee.umbc.edu/~olano/papers/causticvolume.pdf

http://graphics.di.uoa.gr/Downloads/papers/journals/

Various random graphics articles

Parthenon Demo

http://developer.amd.com/wordpress/media/2012/10/Sander-Parthenon.pdf

A Survey and Classification of Real Time Rendering Methods

http://www.merl.com/papers/docs/TR2000-09.pdf

A Practical Analytic Single Scattering Model for Real Time Rendering.

http://www.cs.berkeley.edu/~ravir/papers/singlescat/scattering.pdf

ATI PDF database search

http://search.amd.com/us/_layouts/search/search.aspx?collection=all-us&csquery=Ati&filter=doctype%3aAdobe+Acrobat+PDF&sortby=$score&hits=10&offset=0

Real-Time Realistic Rendering of Nature Scenes with Dynamic Lighting

http://www.kevinboulanger.net/publications/thesisKevinBoulanger.pdf

Gives a good read into real-time rendering of grass and trees with advanced lighting techniques and LOD implementation. Includes some psuedo- code

http://courses.essex.ac.uk/ce/ce318/www/documents/references/3dGraphics.pdf

A huge article with tons of graphics information including -

Simulation of Wrinkled Surfaces Revisited

http://image.diku.dk/projects/media/morten.mikkelsen.08.pdf

A general method for preserving attribute values on simplified meshes

http://vcg.isti.cnr.it/publications/papers/rocchini.pdf

Appearance-Preserving Simplification

http://www.cs.unc.edu/~geom/APS/APS.pdf

Shader Performance Analysis on a Modern GPU Architecture

http://www.csh.rit.edu/~oguns/ps3/vmoya.pdf

Contemporary GPU system architecture

http%3A%2F%2Fwww.compsci.hunter.cuny.edu%2F~sweiss%2Fcourse_materials%2Fcsci360%2Flecture_notes%2Fgpus.pdf

CUDA and OpenCL --- Development Interfaces for Multicore Programming

http://lime.weeg.uiowa.edu/mihpclab/presentations/staffPresentations/2009_12_23_CUDA%20and%20OpenCL%20Development%20Interface%20for%20Multicore%20Programming.pdf

Interactive Horizon Mapping

http://research.microsoft.com/~cohen/bs.pdf

Automatic Shader Level of Detail

http://www.cs.unc.edu/~olano/papers/aslod.pdf

http://www.ati.com/developer/gdc/D3DTutorial07_AlexEvans_Final.pdf

Crafting Physically Motivated Shading Models for Game Development

http://renderwonk.com/publications/s2010-shading-course/hoffman/s2010_physically_based_shading_hoffman_b.pdf

Point Based Color Bleeding

http://graphics.pixar.com/library/PointBasedColorBleeding/paper.pdf

Stupid Spherical Harmonics (SH) Tricks

http://www.ppsloan.org/publications/StupidSH36.pdf

Pitfalls of Object Oriented Programming

http://research.scee.net/files/presentations/gcapaustralia09/Pitfalls_of_Object_Oriented_Programming_GCAP_09.pdf

Multi-core is Here! But How Do You Resolve Data Bottlenecks in PC Games?

http://developer.amd.com/wordpress/media/2012/10/AMD_GDC_2008_MW.pdf

The Technology Behind the 3D Graphics and Games Course “Unreal Engine 4 Elemental demo”

http://www.unrealengine.com/files/misc/The_Technology_Behind_the_Elemental_Demo_16x9_(2).pdf

CPU Caches and Why You Care

http://www.aristeia.com/TalkNotes/ACCU2011_CPUCaches.pdf

paulbourke.net/geometry/p­olygonise/index.html

http://www.realtimerendering.com/

Many free resources to graphics programming

http://jcgt.org/issues.html

http://kesen.realtimerendering.com/

http://graphics.cs.brown.edu/games/SteepParallax/

http://www.gamedev.net/topic/624752-glossy-screen-space-reflections/

http://www.gamedev.net/blog/1323/entry-2254101-real-time-local-reflections/

http://www-graphics.stanford.edu/papers/surfacefitting/

http://www.arcsynthesis.org/gltut/index.html

http://www.realtimerendering.com/

Gives an excellent amount of resources on many areas of computer graphics.

http://http.developer.nvidia.com/GPUGems3/gpugems3_part01.html

Nice resource for many different areas of programming a GPU, a must read

http://rbwhitaker.wikidot.com/index-and-vertex-buffers

Index and vertex buffers explained.

http://cellperformance.beyond3d.com/articles/index.html

Toward Photorealism in Virtual Botany

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter01.html

Terrain Rendering Using GPU-Based Geometry Clipmaps

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter02.html

Inside Geometry Instancing

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter03.html

Segment Buffering

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter04.html

Optimizing Resource Management with Multistreaming

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter05.html

Hardware Occlusion Queries Made Useful

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter06.html

Deferred Shading in S.T.A.L.K.E.R

http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter09.html

http://macton.posterous.com/roundup-recent-sketches-on-concurrency-data-d#

http://assemblyrequired.crashworks.org/2009/01/04/fcmp-conditional-moves-for-branchless-math/

http://seven-degrees-of-freedom.blogspot.com/2009/10/latency-elephant.html

http://osl.iu.edu/~tveldhui/papers/Expression-Templates/exprtmpl.html

http://graphics.stanford.edu/papers/envmap/