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

White posterboard with inscription in black ink. Writing bleeds through to back.

Hallmark card from a member of St. Peter's Episcopal Church in Londonderry, New Hampshire. The inside reads: "Please know that you are in our thoughts and prayers. St. Peter's Episcopal Church Londonderry, NH."

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: "Everyone will stand with you through these tough times. -Flynn."

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter is dated 11/4/18 and reads: "To our people of God. Our prayers of love and support are with you always. The loss of your friends and family is horrible. Our prayers for healing are with you all. God promises in Malachi 4 that 'Goodness will shine like the rising sun and will bring healing.' Take heart. With love, Liliana [last name redacted]."

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.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter is dated Nov. 4 and reads: "Dear Tree of Life Members, We send our love and sympathy to you. We stand by you and all your global family for life. You are our brothers and sisters cherished our heritage through your and our future promises with you. With prayers and love, Rev. Dr. Larry [last name redacted]."

Rectangular piece of plywood wrapped in metal with embossed design of Hebrew word "Chai," meaning "Life."

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.

Folded card with colored pencil illustration. Cover shows a whimsical landscape with a tree, balloon, bushes, rainbow, flower, and a sun. Inside reads: "Stay strong, we're all standing with you. A little hope can go a long way [heart]. Best wishes; this too shall pass". Back cover reads: "2018."

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.

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

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 love you! God is with you always!" The church's contact information is included on the back of the envelope.

Folded card on white paper. Blue, purple, and yellow stains in the center and upper right and left. Mild dirt staining throughout. Due to exposure to the elements at the Wilkins memorial, the message on this card is no longer visible.

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 messages of condolence, love, and wishes for strength. The church's contact information is included on the back of the envelope.

Handmade sign with the words to the traditional Jewish mourning prayer, "Kaddish," transliterated into English and written in pencil. The text is enclosed in a cloud-shaped thought bubble outlined in black. The Stronger Than Hate Steelers' logo with a Star of David appears in the foreground.

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 words of support and prayers for God's love. The church's contact information is included on the back of the envelope.

Folded card with marker illustrations, decorated with stickers. Front features illustration of animal with word bubble "Hi" surrounded by a feature, two balloons, and a kite. Interior features illustration of snowflake and cartoon faces inspired by five emoji stickers and the sender's name "Sadie [last name redacted for privacy]."