Form Ranger allows you to auto-populate the choices in list, multiple choice, checkbox or grid question options from columns of data in any Google Sheet or Doctopus roster.

Great for ensuring form choices match values in an existing database of records, such as students, inventory items, expected attendees, workshop or session titles, etc. -- useful for then applying matching formulas such as COUNTIF, VLOOKUP, MATCH, and others.

Can be set to repopulate options on form submit -- opening the possibility of (somewhat) dynamic form options provided you are willing to explore spreadsheet formulas.  For example, use spreadsheet formulas like IF and COUNTIF in the form spreadsheet to produce a "shrinking" list of options with availability.  Likewise, produce a "growing" list of checkbox options by applying the UNIQUE formula to a list of open-ended submissions, leaving the "other" checkbox option turned on.

For users of the popular Doctopus Add-on for sheets, Form Ranger includes rosters (student name lists) automatically.