latex-dev?

[Karl Berry]

    Did I misconfigure anything

If you take the defaults, there is nothing in particular to "configure".
I surmise you did not install the full scheme.

    have they been forgotten? 

Well, "latex" etc. is in TL20, if that's what you mean :).

    And how can I add the missing ones?

tlmgr install latex-bin # for latex,pdflatex,lualatex
tlmgr install xetex     # for xelatex

That should be enough to make the formats, but other common
packages may be lacking, depending on what you installed.
Thus I recommend also:

tlmgr install collection-latex
and probably also
tlmgr install collection-latexrecommended

Those commands will install the formats too. Hope this helps. --best, karl.