If I have the same author twice in my reference list, and one work is dated and the other is not, which comes first in the list? E.g.: Lastname, F., (n.d.). Title [etc.] Lastname, F., (2019). Different title [etc.]
This has been described quite clearly on the APA Style Blog:
An “in press” work has yet to be published, so if you have one or more references that contain a publication year, these references will always come before an “in press” reference because they’ve already been published.
When dealing with “no date” references, simply follow the same “nothing precedes something” guidance that the Publication Manual gives regarding alphabetizing author surnames in the reference list (see p. 181). Using this guideline, “no date” references should always precede references with “some date.” Also remember that “no date” is abbreviated as “n.d.” in both the reference list and the in-text citations (see p. 185).