In Pokémon Mystery Dungeon: Explorers of Sky/Time/Darkness, there exists the ability to upload SOS Mail to a server, which players can then download to complete, and send back as A-OK (to allow players to continue in areas in which they are stuck.) These are either able to be downloaded in either registration order, fewest undertakers (ie few players have downloaded), or by the specific registration number. AFAIK, no public dumps exist for this, but as this is a part of the Pokémon series (albeit a side-game), it'd be cool to see the functionality implemented. Currently I've taken a packet dump of the server's 98020 inducing response, which has been sent to you via Discord