These are published directories which are usually listings of archives, either as a list of what is owned by a specific institution or a list of archives in a topic. Sometimes it can be combination of the two. You should always remember that another source of archives is already published scholarship, where any archival collections should be listed in the bibliography. Dissertations often list archival collections as a specific section, so these can be extremely useful, especially for hard to locate collections (and institutions).
In searching Bobcat you can always use the keyword subject search "Archives Directories." If you add another term, New York as a geographic subject for example, you can quickly limit the search. The trick is that not every possible term is used, and the third term may take out materials you would want to see, so fiddle with any additional subjects.
The first two focus on archives and are available via NYU's subscription. The second is a union catalogue which only has those institutions contributing to it. There is overlap with the records in Archive Grid. Archive Finer lists many collections not in either WorldCat or ArchiveGrid.
Recommendations from Peter Wosh, Head of the Archives and Public History Program, are marked with an asterisk.