I don't know how this would be useful to someone reading the cheat sheet, but here's something interesting I just indirectly found out while skimming it through:

Ctrl+D does the same thing as ENTER, except the latter additionally sends the end-of-line character to the reader while the former sends nothing;
as is the case for shells or interactive programs like the Python REPL, Ctrl+D causes them to terminate only because it sends a string that is 0 characters long, and 0-size reads are universally interpreted as files reaching the end.

To test this: enter cat, type "hello" without pressing enter, then Ctrl+D: you should see "hellohello".
An extremely rare case of this being useful would be using netcat to send a string somewhere, without sending the end-of-line byte at the end.