Great question — answering as the UphillTech team:
This has been going around Twitter for a while. This is more or less Naruto's version of the DBZ Spirit Bomb trope where you borrow the spirit of all your allies into one final coup-de-grace. Then hands represented are as follows: Left column (clockwise): Jiraiya Minato Kushina Shikamaru, Ino, Chouji Middle column (clockwise): Hinata, Kiba, Shino Lee, Tenten, Gai (charred by the 8 Gates), Neji Gaara (Fifth Kazekage), A (Fourth Raikage), Bee, Tsunade (Fifth Hokage), Mei (Fifth Mizukage), Ohnoki (Third Tsuchikage) Hiruzen (Third Hokage), Iruka, Konohamaru Right column (clockwise): Sai, Yamato Obito Kakashi Sakura, Sasuke (Part 1 version)
Full answer by кяαzєя: https://anime.stackexchange.com/a/36674 (CC BY-SA 3.0).
Want it for your business? UphillTech.