This is a complete* list of Massachusetts state-listed species which can be used as a personal search query to quickly propagate all observations one has observed of state-listed species.
To view all of your observations of state-listed species in Massachusetts add your username to this link and paste into your browser.
https://www.inaturalist.org/observations?list_id=3831895&place_id=2&subview=grid&user_id=(yourusernamehere)
Using this as a tool, one can then submit these sightings to Massachusetts Natural Heritage and Endangered Species Program's Vernal Pool and Rare Species (NHESP VPRS) information system.
These observations are critical for the state's monitoring of these species and can also have major conservation and land preservation implications. Given that iNaturalist observations provide all of the necessary data required to confirm reports of these species I would urge all to submit all of their observations of state-listed species to the database, as Massachusetts DFW is unable to pull data from the iNaturalist database.
More info on NHESP, VPRS, and the portal to submit observations can be found here! https://www.mass.gov/service-details/vernal-pool-rare-species-vprs-information-system
*Does not include Sunderland Spring Planarian, Seidlia remota or Ostrich Fern Borer, Papaipema sp. (latter is undescribed)