Battle designer from SaGa is lead designer on LoL, which is, in turn, widely considered a spiritual successor to the SaGa series. So, I'll count it, though with the caveat that it does also share some Final Fantasy series staff and so may as well be considered this for FF too.
WinkySoft developed all the early Super Robot Wars games for Banpresto, including Super Robot Wars Gaiden Masou Kishin - The Elemental Lords (or The Lord of Elemental) in 1996. They stopped working for Banpresto in 2000, and released a spiritual sequel to Masou Kishin called Seireki Rayblade for the PSX and Dreamcast that same year. Not only is the gameplay system similar, the main character looks almost the same and the premise of the story is very similar (though it supposedly goes in another direction from there).
In 2010, WinkySoft collaborated with Banpresto again after 10 years for a remake of Masou Kishin for the DS, which lead to them making three actual sequels. Meanwhile, they also cancelled a planned Seireki Rayblade 2 at some point.