Saturn has the entire Langrisser series, and with the exception of the PC-FX version of Der Langrisser, it has the best versions as well. Langrisser IV is simply put the absolute best SRPG ever made. A shame theres no English version.
Magic Knight Rayearth. You know I hate everything MKR related (manga, TV show, CLAMP, etc) but this game is so stupidly good thanks to Working Designs that I've played it through about 6 times.
Albert Odyssey (Albert Odyssey Gaiden in Japan), a really great RPG that no one bought because "it looks like an SNES game." Oh how I hate my fellow Americans
Black/Matrix (Japan only), this game has some serious flaws, but its still better then both B/M AD on Dreamcast and B/M Cross on PS1. Also this was the start of the fantastic B/M series. Still praying that Flight-Plan would finish the damn series all ready.
I loved the rendered sprites from Shining the Holy Ark. Can't believe I forgot that game, its still one of the best dungeon crawlers ever. The dungeon designs were pure genius. If only we could get a new Shining game like this one.
Though I really like RPGs, I actually haven't had too many gos for Saturn RPGs. I'm more of an oooold-school RPG player, so I tend to play the pre 32-bit generation RPGs.
Grandia was pretty cool as well. I also played the PS version back in its day - never tried the Saturn version. I heard it was much better (but the language barrier was a much bigger issue back then for me).
It's a crime some of these Japanese RPG's were never translated......A real shame......I have heard Princess Crown is a pretty good Jap title for non Japanese speakers......not to sure how true that is.......