There's not. There's Sho Tanaka, Yohei Komatsu, Takaaki Watanabe (currently on excursion). El Desperado is an other ex-young lion of the generation, and Hiromu Takahashi is in CMLL wrestling as El Kamataichi on excursion.
Granted, five isn't all that much, but New Japan's training standards are ridiculously strict, which combined with the far looser set up of bringing in freelancers + longevity of their wrestlers means turnover isn't as quick.
Problematically though, NJPW needs more rookie heavyweights. They've got a serious dearth of those, and even if a lot of their guys (Ibushi, Shibata) aren't anywhere near the required weight, they need more fresh blood.