OpenTK supports various optional dependancies. These are meant for your convenience and are completely optional to use.
SDL2.dll libSDL2.dylib libSDL2.so
The Simple DirectMedia Library compiled for Windows, Mac OS X and Android.
Simple DirectMedia Layer is a cross-platform development library designed to provide low level access to audio, keyboard, mouse, joystick, and graphics hardware via OpenGL and Direct3D.
OpenAL32.dll
OpenAL Soft is an LGPL-licensed, cross-platform, software implementation of the OpenAL 3D audio API, and is required to use OpenAL on Windows. Linux and Mac OS X support OpenAL out of the box.
libEGL.dll libGLESv2.dll d3dcompiler_46.dll
The goal of ANGLE is to allow Windows users to seamlessly run WebGL and other OpenGL ES 2.0 content by translating OpenGL ES 2.0 API calls to DirectX 9 or DirectX 11 API calls.
On Windows, OpenTK supports the following additional DLL seach paths: OpenTK Folder\x86 - Place x86 architecture specific files in this subfolder. OpenTK Folder\x64 - Place x64 architecture specific files in this subfolder.
Please also see the following Microsoft link for a full explanation on the DLL search order: https://docs.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-search-order
Under Linux and Mac OS X, the search path for these optional dependancies may be found in the OpenTK.dll.config file, which should be placed next to OpenTK.dll The Mono documentation for this file may be found at the following page: https://www.mono-project.com/docs/advanced/pinvoke/dllmap/