The EXT_texture_compression_bptc extension for WebGL 1.0 and 2.0 contexts adds the BPTC compressed texture formats to compressedTexImage2D() and compressedTexSubImage2D().

The EXT_frag_depth extension for WebGL 1.0 and 2.0 contexts adds setting the depth value of a fragment from within the fragment shader.

The WEBGL_draw_buffers extension for WebGL 1.0 contexts enables a fragment shader to write to several textures, which is useful for deferred shading, for example.

The WEBGL_multi_draw extension for WebGL 1.0 and 2.0 contexts renders more than one primitive with a single function call.

The OVR_multiview2 extension for WebGL 2.0 contexts renders into multiple views simultaneously. This especially useful for virtual reality (VR) and WebXR.

The EXT_float_blend extension for WebGL 1.0 and 2.0 contexts adds 32-bit floating-point components to blending and draw buffers.

The KHR_parallel_shader_compile extension for WebGL 1.0 and 2.0 contexts checks the status of shader compilation without blocking the runtime.

The WEBGL_compressed_texture_s3tc_srgb extension for WebGL 1.0 and 2.0 contexts adds S3TC compressed texture formats for the sRGB colorspace to compressedTexImage2D() and compressedTexSubImage2D().

The WEBGL_compressed_texture_s3tc extension for WebGL 1.0 and 2.0 contexts adds S3TC compressed texture formats to compressedTexImage2D() and compressedTexSubImage2D().

The WEBGL_compressed_texture_pvrtc extension for WebGL 1.0 and 2.0 contexts adds PVRTC compressed texture formats to compressedTexImage2D() and compressedTexSubImage2D().

The EXT_disjoint_timer_query extension for WebGL 1.0 contexts measures the duration of a set of GL commands, without stalling the rendering pipeline.