Xenogears, Grandia, Symphony of the Night, Vagrant Story, Alundra, Parasite Eve (1), Final Fantasy Tactics. All these are still worth it, imo.
Most of these don’t have next-gen sequels or similar titles that surpass them.
Grandia is a must, since you may wanna play what we “should” have gotten on the Saturn back in the day, yet the release stayed in Japan until much later where it was ported to the Station and released internationally. It doesn’t hurt that it’s great.
I suppose you could get Dawn of Sorrow on the DS instead of Symphony of the Night, but the latter is kind of the original and the largest metroidvania yet, before they felt they had to add strange new gameplay hooks to entice players, which doesn’t always work.
Xenogears is Square’s best effort of the era despite some shortcomings. It feels very unfinished in places for sure, but the overall product is still good, and in my opinion has similar mystique to the Panzer Dragoon world at times. The Gears in question are weapons unearthed with excavations of the powerful nations after all.
Parasite Eve’s story is kind of like Deep Fear except actually done very well, involving biological stuff with a dose of the supernatural, while the gameplay’s kind of a survival horror JRPG, with conventions from both genres, though mostly the latter.
Final Fantasy Tactics, the original. Well, it’s my favorite tactics game and has my favorite story but I suppose if the story doesn’t hook you then there are other tactics games to go for just as well, but due to its nature it doesn’t really feel outdated anyway. It plays similarly to Tactics Ogre titles with a Final Fantasy skin for the item names, the fauna, etc. The story felt pretty epic at the time, despite the shoddy translation. There’s a PSP re-release to consider. It replaces many cut scenes with CG anime that is not always successful, but the new translation’s told to be much better.
Vagrant Story’s gameplay is kind of an evolution of the system in Parasite Eve. It’s more varied and has a combo system and other elements. The pace however is not similar at all, so if you dislike one, you should still try the other. The story is of course completely different and at times feels like a fantasy Metal Gear Solid, though it often goes to JRPG shenanigans that are no less engaging. I think this is one of Square’s best efforts also, though the gameplay later focuses too much on block puzzles which kind of stops the game from feeling like a true classic. The art style is a dark and gritty evolution of the art style used in Final Fantasy Tactics. I love it in both games, but it’s more prominent in this.
Alundra, well, it’s the PlayStation’s Zelda. It’s 2D so it shouldn’t feel too outdated itself.