
The PS1 era. The SNES's RPG library, while it has some enduring classics, was pretty dependent on Square, at least in the US since Dragon Quest V and VI were not localized. The PS1 and PS2 had a much deeper and broader library of RPGs. We had a lot more different styles of RPG on PS1 and PS2, including some of the best SRPGs, and companies like Capcom, Namco, Konami, Working Designs, Tri-Ace, Level-5, Atlus, and many others contributing to the PS1/PS2 RPG pool.
I'd honestly say that the Nintendo system with the best RPG library is the Switch, and the Switch is damned near an RPG golden age in itself that's coming pretty close to the PS1. DQXI, Fire Emblem, Xenoblade, Valkyria Chronicles, and SMT V are all amazing.