There are various obscure commands and options in *nix. Some are easier to associate to like: q for quit and so on. I am pretty sure that all the command names and options name have some meaning behind. Please keep sharing what you know or point to some resources on net. I searched for a while but didn't get a good resource.
Questions asking for learning materials are off topic here, unless it's related to the official POSIX documentation of standard utilities.
There you may find a list of all shell utilities and each utility described in detail, including what their options do, and often even examples of use.
You should also read the manual on your system for the tools that you use to familiarise yourself with them. The utilities on your system will likely be mostly POSIX compliant, but may well extend their repertoire of usage beyond what's required by the standard. Other tools are simply not standardized because their use falls outside of what the standard applies to.
When it comes to the letters used for options; Some utilities have lots of options, and it would be difficult to find meaningful names for them, especially if only the short one-letter options are used. However, options that are used across multiple utilities often (but not always) has the same name and semantics, such as
-d for "delimiter", or
-o to specify the name of an output file. The Rationale section of some standard POSIX utilities may give the reasoning for the particular choice of options in some cases (like the discussion about the
-c option for