"The Gospel of John is the only Gospel which mentions “the disciple whom Jesus loved.”"
https://www.gotquestions.org/disciple-whom-Jesus-loved.html
"In John’s Gospel there is mention of “the disciple whom Jesus loved.” This disciple (an apostle really) is never mentioned by name."
http://blog.adw.org/2010/06/identifying-the-disciple-whom-jesus-loved/
"According to the Gospel of John, this was the disciple who leaned on Jesus during the Last Supper, and the only male disciple present at the crucifixion"
http://www.gospel-mysteries.net/beloved-disciple.html
"20Peter turned around and saw behind them the disciple Jesus loved—the one who had leaned over to Jesus during supper and asked, “Lord, who will betray you?” 21Peter asked Jesus, “What about him, Lord?”
22Jesus replied, “If I want him to remain alive until I return, what is that to you? As for you, follow me.” 23So the rumor spread among the community of believers that this disciple wouldn’t die. But that isn’t what Jesus said at all. He only said, “If I want him to remain alive until I return, what is that to you?”"
https://biblehub.com/nlt/john/21.htm