Oh, man, so many great RPGs on the system. Of the ones I've beaten that aren't from the big two:
Xenogears - Great game that loses steam on the second disc, but still excellent. Just wish that text wasn't so slow.
Breath of Fire IV - Everyone seems to love
BoFIII, but for my money,
IV is where it's at. Loved it the entire way through.
Parasite Eve - Shorter than the usual, but that's actually good. A very, very fun playthrough, especially this time of year.
Alundra - Yeah, I dug the mess out of this one. You can definitely tell it's the
Landstalker folks. You might want to consider the UnWorked Designs version that restores enemy HP to the Japanese version's values. And you know what, everyone bags on
Alundra 2, but I really liked it as well. Just a big tonal shift - much more
Mega Man Legends cartoon-style, less grimdark.
Suikoden I & II - I'm throwing these together, 'cause they're both great. The original is a short, well-paced classic. The second takes some time to get going, but can potentially claim best of the series.
Legend of Dragoon - Probably a little rougher than I remember it, but if you like
Final Fantasy on PSX, this is also good. Just be aware that localization is pretty stiff.
Chrono Cross - Bad as a follow-up to
Chrono Trigger, but a great game nonetheless.
Legend of Mana - Very slick brawler/RPG hybrid that's got lots of replayability.
Vagrant Story -
Parasite Eve's combat system on crack, and one of the most gorgeous and well-localized games on the system. Seriously, it looks amazing.
Valkyrie Profile - One of the most unique RPGs on any system. Great story, with a very melancholy feel pushed along by one of Motoi Sakuraba's best soundtracks. Just... don't expect to get the best ending without a guide.
Grandia - Very slow start, but it turns into a fantastic RPG. Very much Game Arts at the pinnacle of their powers. It might be worth playing that one on Saturn, though - there's a translation for it now and it performs better than the PSX version, but the PSX game is still plenty playable.
Arc the Lad II - I feel like you need to play
AtLI to get the most out of it, which is a very short and easy SRPG.
AtLII is like the
Chrono Trigger of that series. Absolutely a must-play if you dig
Shining Force.
SaGa Frontier II - Probably the most accessible of the series. Also gorgeous.
I hesitate to recommend the
Wild ARMs games - I think they're right on the cusp of a recommendation, but I haven't beaten the first game, and it's been quite some time since I played through
WA2. But they're solid at a minimum.
Koudelka gets a hesitant recommendation for everything that isn't the combat system.
As for ones I don't really recommend today - I loved
Tales of Destiny back in the day, but that random battle rate is just bruuuuutal.
Eternia/ToD2 didn't hold my interest to finish it, but I do think it's better. I know
Ex digs
Threads of Fate, but I've never been able to finish it. But it's definitely worth some run.
Ones I want to finish some day include: the aforementioned
ToD2,
Brave Fencer Musashi,
Thousand Arms,
SaGa Frontier (I'd probably do that with the remaster), and the
King's Field games.