Post-it note with handwritten message in blue marker. The message reads: "My heart, my grief, my compassion, and my best wishes are with all of you. Love, Cherlz from L.A."

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.

Post-it note with handwritten message in black marker. The message reads: "When we work together, hate can't win. -Max S."

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.

Post-it note with handwritten message in red marker. The message reads: "99.9999999% of Americans are good and caring people!" Tape on the upper edge.

Blue card with a Star of David filled with flowers outlined in gold and silver ink on the front cover. The inside contains a lengthy, heartfelt letter from a sender identifies themselves as "an angry college student who wants a change" from Pittsburgh.

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 reads: "We [a]re with you. We love you. We care about you." The church's contact information is included on the back of the envelope.

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.

Hand painted card. The card contains the Stronger Than Hate symbol with a yellow Star of David on the left. The words: "Stronger than Hate" appear in a black text box to the right. A heart appears above.

Handwritten card from a student at Goddard Middle School in Littleton, Co. The front cover reads: "F.e.a.r. has two meanings- Forget everything and run OR Face everything and rise. The choice is yours." A star of David and cartoonish illustration of a smiling boy wearing a red baseball cap appear below; a shining sun in the upper right corner. The inside reads: "Dear Rabbi Jeffrey Myers, We are sorry for your loss and we hope you are recovering well. -Aiden G. Littleton, Colorado." Spelling errors corrected for clarity.

Black and white sticker with the word "LOVE" in large capital letters.

Triangle-shaped card from a student at Fountain Valley School in Colorado Springs, Co. The card reads: "Dear members of Tree of Life, I am a Chinese [student] who is now studying in U.S. I am sorry about the situation that happened recently. Personally, I support you, do not be afraid! Peace be with you." Star of David in the upper center, peace sign in the bottom center.

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of seven children holding hands around a table with a large goblet and loaf of braided bread, and seven doves. The illustration is labeled: "We are people of God's peace." The inside reads: "We are praying for you." The card has been embellished with multi-colored horizontal lines.

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.

Hardwritten card in blue pen on white paper, offering condolences following the October 27 attack.

Hallmark card from a member of St. Peter's Episcopal Church in Londonderry, New Hampshire. The front cover reads: "Faith is the friend that comes along when things just seem to go all wrong." The inside reads: "You are not alone in this tragedy. We will pray for God's peace for your community. Love is stronger than hate. Colleen and Michael."

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of seven children holding hands around a table with a large goblet and loaf of braided bread, and seven doves. The illustration is labeled: "We are people of God's peace." The inside reads: "We must stick together in times like these because together we are STRONG and no one can take that away from us. Enzo."

Post-it note with handwritten message in black marker. The message reads: "May god be with you. Cierra [last name redacted]. Pittsburgh, PA."