Well, just some examples I can think of right now are Yamamoto, who suddenely made a comeback in Cutting Edge 20 after almost 5 years out. There's also Aoba, who was absent for a year before making a shocking return and getting barebacked and creampied in 生堕ち!! 005. Matsuda (aka Tomoki) was about 4 years out from his last work with another studio before making an appearance for COAT earlier this year. Then, there's also "He who must not be named" (aka Biracial Twink Student) was two years out from his last work before last month's return. Also supposed to be another one this October with Seto (
https://md.gvdb.org/20130/) in Joint 08 after almost 3 years from his last work.