> So, basically something like list.el containing:
>
> (defalias 'list-append 'append)
> (defalias 'list-map 'mapcar)
> (defalias 'list-add 'add-to-list)

We have seq-append and seq-map for the first two; do we need the list- versions too?

No of course we don't. It might make more sense to enhance seq to cover all list/vector operations.