I'm honestly wondering just how close to the line someone could tread, with regards to trying to clone existing sub-races/sub-classes, etc. If the name of them isn't anything that's closed, and you can use whatever game mechanics are in the 5E SRD, then so long as it's not word-for-word the same I suspect you could recreate quite a bit of what's not there.
Although the real question would be why anyone might want to bother? I mean, unless you just felt like you HAD to have a Wood Elf using PC stats rather than a monster statblock in an adventure you were writing ... would anyone actually buy a non-5E-SRD "Wood Elf" subrace created and posted onto the DM's Guild? Who would do that? What would be the point?