I could suggest you two variants of solutions. First, you could buy few old books with algorithms, where good terms on use IP and just implement them. Usually,

I could suggest you two variants of solutions. First, you could buy few old books with algorithms, where good terms on use IP and just implement them. Usually, this mean, new patents could not prohibit usage of IP which is published before patent appear. Second, you could join some technology consortium, like OpenGL, or Vulkan, or W3C, or may be even GNU/Posix, and use only technologies, which this consortium linked to, usually membership includes rights to use their IP, and they defend their members from patents issues. This is more expensive than old book, but may include more modern algorithms. Using any of these variants, you will early know, what you near guaranteed to use, and will have predictable future.