Timsort
Timsort is a stable hybrid sort used by CPython and (historically) Java’s object Arrays.sort. It finds natural ascending or descending runs, sorts short runs with insertion sort, then merges them with a merge-sort strategy and carefully chosen run-stack invariants.
On random data it is still $O(n \log n)$. On nearly sorted data it can be close to linear because long runs need little work. That is why “just call the language sort” is usually the right default unless you have a special key domain.