5. Moegi Kazamatsuri
Moegi Kazamatsuri is a former comrade of Konohamaru Sarutobi and is also a Jounin level shinobi of Konohagakure. She has the ability to use the all-powerful Kekkei Genkai ability of Wood Release like Hashirama Senju. So, it is possible in the near future she might be able to use Hashirama Senju like Sage Mode which he was able to use due to his Wood Release, and thus we will get an all-new sage mode user.
Jigen is the leader of the organisation named Kara. He also has a similar Karma seal that Boruto Uzumaki has, meaning that he has already acquired the power of an Otsutsuki clan member. And if Kashin Koji is able to use the Sage Mode of Mount Myōboku it is possible that Jigen might have learnt it as well, as it is an awesome powerup to have during a long and hard battle.