So, a few things (aside from the whole nomenclature argument already in another reply) 1

> There's a single "I guess I would use this" container type, std::vector. About that one... I would claim that in a majority of cases where an std::Vector is used, what the author really wanted was a similar type, but whose size and capacity are fixed on construction and never change. The standard C++ library does not offer such a type - so people use vector because it's handy. Agree with your takes on most of the containers. I also dislike how optionals are never used with containers as they were standardized later (and even then, problematically w.r.t. references). Thus, for example, if I lookup an object in a map of T's, the result should IMNSHO be an optional reference to a T.

I would argue that even the basic concept behind STL is misguided. The rationale I often see is "you only need N algorithms for M container type, instead of N*M". This ignores the fact that algorithms and data structures are not independent of each other, and also that most of the time these days you're operating on vectors, so M ~= 1. Case in point: list::sort. You don't want to try running quicksort on a linked list. Or remove_if: great we've abstracted the difficult task of removing things without erasing them, except we can't do it on maps. (C++20 seems to add an erase_if, apparently admitting that the two-step remove/erase is silly). Then there's the fact that C++ iterators are basically pointers into the data structure, where for vectors (your common case) you'd do much better with index/container pairs, both for stability and bounds checking.

AFAIK, std::map is also OK for what it is: an ordered, node-based (tree) map. These are (almost) always slower than hash tables. Of course, std::unordered_map, the std hash table, sucks because of unforced errors. For that, there is boost::unordered_flat_map.