Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of a haloed dove flying in front of Noah's ark. The inside reads: "I am sorry for your loss. From: Holy Angels CCD."

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a leaf with floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside contains prayers for peace and unity. The church's contact information is included on the back of the envelope.

Card from two families in Edgewood, Pa. Front cover shows an illustration of two hands holding a cat's cradle yarn configuration with stars. Message expresses thanks to victims and their families.

Folded card with marker and colored pencil illustration. Front and back cover feature spread of tree emerging from blue field. Interior features scribbles and name "Veronica." Additional message reads "Our hearts go out to you at this tragic time, along with our wishes for healing. The Beth Chai Congregation of Greater Washington, D.C."

Post-it note with handwritten message in black marker. The message reads: "What happened here will not be forgotten." Signed with a Star of David.

Letter written on a piece of notepad paper with a blue line on the right edge. The note reads: "To the loved ones lost, 'Magnified and sanctified be Your name.' Always remembered. The [last name redacted] David, Alyson, Theodore and Andrew."

Post-it note with handwritten message in black marker. The message reads: "Rest in Peace. Toronto."

Post-it note with handwritten message in blue marker. The message reads: "May their memories be a blessing. Love [heart] From Charlotte, NC." Tape on the upper edge.

Handwritten note in pencil on paper. The note, written in bubble letters, reads: "Stronger Than Hate." Illustrated with the adapted Steelers emblem with two diamonds and a Star of David. Creasing and fading due to exposure to the elements at the Wilkins memorial.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter is dated Nov. 4, 2018 and reads: "Tree of Life, I give thanks daily to Yahweh, Father Abraham, Moses, and Jesus! We are all one with you, bonding with you, suffering with you, and healing with you! God help us all daily to Love, Joy, and Peace! Please let our pastor Karla Shaw know how we can help further! Shalom, Larry A. [last name redacted] Semper Fi America! San Diego, California."

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter reads: "We are shocked that this individual felt he could do such a thing. Who gave him the power to act as God? All our prayers are with your community and faith. Blessings! A sad Presbyterian member!"

Handmade card illustrated in pink and blue colored pencil featuring assorted hearts in varying shapes and colors. Color bleeding due to exposure to the elements at the Wilkins memorial.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a turtle with floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."