On the user side, most of that can be stored in the resource section (for PE format executables, so Windows only for all practical intents and purposes). It has annoyed me many times that no such thing exist in Unix land (ELF, basically), and instead I have to rely on 'bin2hex' style tools and store that data in the data section.

Elf has the concept of sections, and you can make as many of them as you want. The standard gnu Linker also automatically creates labels that you can use to get ahold of those sections. For example for a section titled XYZ, it'll automatically create to extern variables named __xyz_start and @__xyz_end sorry some such thing. You can place things into sections from source code, or add them later using objcopy

Well yes, let me rephrase then: it's a shame there is no standard API to categorize and access data in other sections.