Is there a more up to date listing of extension by card than the one on www.gamedev.net/opengl?
In particular I am looking for cards that support GL_ARB_vertex_blend.
Perhaps if a more up-to-date listing does not exist, we could start one in this thread.
Extensions are not supported by card. They are supported by OpenGL implementations. As drivers change, new extensions on existing hardware may appear (like register_combiners did for GeForce’s).
If you want to build such a database, here’s the extensions for Radeon, which supports your wanted GL_ARB_vertex_blend extension.
GL_ARB_multitexture
GL_ARB_texture_border_clamp
GL_ARB_texture_compression
GL_ARB_texture_cube_map
GL_ARB_texture_env_add
GL_ARB_texture_env_combine
GL_ARB_texture_env_crossbar
GL_ARB_texture_env_dot3
GL_ARB_transpose_matrix
GL_ARB_vertex_blend
GL_ATIX_envmap_bumpmap
GL_ATIX_pn_triangles
GL_ATIX_texture_env_combine3
GL_ATIX_texture_env_route
GL_ATI_texture_mirror_once
GL_ATI_vertex_streams
GL_EXT_abgr
GL_EXT_bgra
GL_EXT_clip_volume_hint
GL_EXT_compiled_vertex_array
GL_EXT_draw_range_elements
GL_EXT_fog_coord
GL_EXT_packed_pixels
GL_EXT_point_parameters
GL_EXT_rescale_normal
GL_EXT_secondary_color
GL_EXT_separate_specular_color
GL_EXT_texgen_reflection
GL_EXT_texture3D
GL_EXT_texture_compression_s3tc
GL_EXT_texture_cube_map
GL_EXT_texture_edge_clamp
GL_EXT_texture_env_add
GL_EXT_texture_env_combine
GL_EXT_texture_env_dot3
GL_EXT_texture_filter_anisotropic
GL_EXT_texture_object
GL_EXT_vertex_array
GL_KTX_buffer_region
GL_MESA_window_pos
GL_NV_texgen_reflection
GL_S3_s3tc
GL_SGI_texture_edge_clamp
GL_SGIS_texture_border_clamp
GL_SGIS_texture_lod
GL_SGIS_multitexture
GL_WIN_swap_hint
WGL_EXT_extensions_string
WGL_EXT_swap_control
WGL_ARB_make_current_read
WGL_ARB_pbuffer
WGL_ARB_pixel_format