I’ve seen them show up in lots of situations through intrusive lists, which I think is the general form of the example you’re giving. Intrusive lists are used

I’ve seen them show up in lots of situations through intrusive lists, which I think is the general form of the example you’re giving. Intrusive lists are used in the Linux kernel, in physics engines (eg Chipmunk2d) and game engines. The way Redis uses them for TTL expiry follows the same pattern.