The Rain catcher note is an optional artifact in a sewer utility room in The Suburbs. After runners and a clicker ambush the group, enter the room on the right and check the table at the back, next to the rain-catching barrels.
A friendly note from Ish praising Susan's idea to collect rainwater indoors. He admits to handing the kids water guns and getting soaked all day, offers to take them back, and warns her that Kyle is cooking his questionable meatloaf again.
It shows the sewer group at its best: settled, fed and joking with each other, a contrast to the notes that follow.
Antiparticles
Antiparticles, issue 11 of Savage Starlight, lies on the console in the bridge of the wrecked fishing boat on the beach at the start of The Suburbs.
Boat note
The Boat note is an optional artifact on the bridge of the beached fishing boat at the very start of The Suburbs. Climb onto the deck, step into the wheelhouse and grab it from the console beside the Antiparticles comic.
Bomb: Containment
Bomb: Containment is a training manual on a shelf in the sewers of The Suburbs. It makes nail bomb blasts 1.5 times wider.
Cornered note
The Cornered note is an optional artifact behind a door near the sewer ambush site in The Suburbs. After the runner and clicker attack, climb the stairs, go through the door on the left and find it on a bench by the bodies in the corner.