Of libraries that are better than the STL? Or data structures that the STL is missing? Without getting into the weeds of esoteric data structures and algorithms

Of libraries that are better than the STL? Or data structures that the STL is missing? Without getting into the weeds of esoteric data structures and algorithms I think there's a few holes that aren't addressed: https://github.com/martinus/unordered_dense https://github.com/martinus/unordered_dense provides better replacements for unordered_map/set. The STL is missing B-trees and B-heaps, as well as d-heaps. STL is also missing a radix sort, which is even more sorely missed now that we have std::executor::par_unseq to play with.