On June 26, 2017, the group released the special digital single "I'm Your Light", sung by Park Woodam, Woo Jinyoung, Jung Woncheol and Jo Yonggeun, as a thank you gift for fans who supported them during Produce 101. HNB released their second special single "You Are So Beautiful" on December 2, 2018, sung by Woo Jinyoung, Park Woodam, and Jung Yoojun.
2019–present: Final line-up and debut
On March 12, 2019, their agency announced the final lineup that will consist of five members: Woo Jin Young, Park Woo Dam, Kim Hyun Soo, Jung Yoo Jun, and Jo Yong Geun. Their group name was decided through a fan vote. On March 27, it was announced that the group will be called D1CE and would debut sometime in the first half of 2019.
- Woo Jin Young (우진영)
- Park Woo Dam (박우담)
- Kim Hyun Soo (김현수)
- Jung Yoo Jun (정유준; formerly Jung Minhwan (정민한))
- Jo Yong Geun (조용근)
- Jeong Woncheol (정원철)
- Park Hyungjin (박형진)
- Lee Jongmin (이종민)
- Jo Yooncheol (조윤철)
- Yoon Jaehee (윤재의)
- Won Hyunsik (원현식)
- Kim Junhyeong (김준형)
- Kim Jungwoo (김정우)
- Kosuke (코스케)
- Wake Up: Roll the World (2019)
- Jo Yonggeun, Park Woodam and Woo Jinyoung, alongside former member Jeong Woncheol, are former contestants of Produce 101 Season 2.
- All current HNB trainees were contestants of MIXNINE.
- Woo Jinyoung placed 1st on the show.
- Woo Jinyoung was JYP Entertainment trainee until the beginning of 2016.
- Jo Yonggeun was a DSP Media trainee from September 2014 until 2016 alongside Produce 101's Choi Dongha.
- Jo Yonggeun appeared in the 1st episode of Gu Hara ON & OFF: The Gossip as one of the DSP Media trainees alongside Joonghee of A-JAX, Dojoon of The Rose, BM, J.Seph and Somin of KARD, Chaekyung and Jinsol of APRIL and Yuji of Apple.B.
- Woo Jinyoung received the nickname of "Loco" during his times as a JYP trainee because of his resemblance to the rapper.
- Park Woodam was supposed to be in BOYS24, but dropped out a few weeks before the broadcast.
- Jung Minhwan was part of BOYS24
- Park Woodam was a mukbang BJ on Afreeca TV.
- Jo Yonggeun and Kim Junhyeong made an appearance in "Fri. Sat. Sun" teasers by Dalshabet alongside Ziu of VAV.