Hi @joeysantore, I revised the title of your request to more directly state the feature your are looking for. Feel free to edit further if I missed the mark.
I approved the request for posting because I don’t know enough about the phone apps to say whether this can already be done there or not. I only use the apps (rarely) to make new observations.
On the web site, however, it looks like you can use your Life List to get the information you are looking for. For example, this returns all the taxa of Phrymaceae you have observed:
You can plug in any Family (or any other taxon you want to list) in the search box. You can also switch between this plain list, and a taxonomic view. At the bottom of the list, there is a link to export the list to CSV or Taxonomic CSV, which you could then manipulate in a spreadsheet to generate PDF output. The site does not support direct output to PDF, other than from the web browser.
Again, don’t know if or how much of this same functionality is available in the apps, but hopefully others who do will chime in.