(Confirmed for certain today that I'll have to do another sweep through the list in order to get new species added after I went through those sections. It's actually kind of exciting.)
501. Jilruans. Jilruans are a "towering" species that seem to have a predilection for serving fat slug-guy races (Hutts and the like). Just how big they are is unclear, because the information on them is kind of inadequate, but they certainly aren't small from pictures, so at least there's that. They seem to have glowing eyes.
Rating: 3/5. They look intimidating and they actually have some history for them... and once again, a lot of them got killed by Yuuzhan Vong, though in this case it seems that most of the victims were actual soldiers. Gotta give them credit for that.
502. Jin. Jin have infrared vision (no word on whether they can see in "normal" visible frequencies) and "rich culture and art."
Rating: 2/5. Whatever.
503. Jin'ha. The Jin'ha apparently specialize in working with cortosis ore, a substance that can be used to short out lightsabers when it gets cut (it's also resistant to being sliced, though only enough so that it wouldn't be cut deeply) and also seemed to like cybernetics... maybe. Apparently, they're a bit mysterious. They also fought Jedi at some point.
Rating: 3/5. A little generous, but they're interesting in appearance.
504. Jindas. Jindas are a species who are spacefarers, but a sizeable population of them ended up on Endor after a spacecraft crashlanded. They used to give a wizard their fine food, but after said wizard broke a tooth on some of their food and came to the crazy conclusion that they were trying to poison him, he put a curse on them that caused rock to come to life and chase them if they stayed in one place too long. This forced them to change their occupation to traveling minstrels.
I am not making this up.
Rating: 3/5. It still makes me smile that technically the Star Wars galaxy has out-and-out magic in it, even if it's handwaved and retconned as somehow being the Force every single time.
505. Jokhalli. The Jokhalli are guys with elongated faces and two arms that branch into two forearms past the elbows. They apparently can speak a Baragwinian trade dialect and are commonly xenophobic primitives. They have a dice-rolling gambling game they like.
Rating: 3/5, mostly because they have a reasonably interesting design.
506. Jostrans. Jostrans are centipede-things of a fairly large size ("human arm-sized"). Their civilization was destroyed when the living planet Zonama Sekot unwittingly disrupted their ecosystem while passing through their solar system. Thereafter, the Jostrans survived by climbing inside the bodies of another species and symbiotically bonding with them (essentially merging with their spines and partly taking over their nervous systems in the process).
How does that even work?
Rating: 1/5. That's... not really how symbiotes and parasites develop, guys. Not in a handful of generations, anyway.
507. Junkers. Junkers may or may not actually be a species as such, because they're really, really cyborgy, for lack of a better term. They are, as their name suggests, technology scavengers.
Rating: 3/5. Mostly because they look neat.
508. Juzzians. Juzzians have cone-shaped bodies, sharp teeth, probably developed the Juzzian armlock, and make/made edgy art.
Rating: 3/5. What a delightful random collection of features.
509. Jumerians. The Jumerians are known to have been part of the Old Republic from very early in its existence, and still present during the New Republic after the fall of the Empire.
Apparently, they gave Leia a singing lamp as a wedding present. She probably didn't like it.
Rating: 2/5. I want to know why they gave her a singing lamp! That's the real interesting part! (And no, I'm actually serious. Did they intend it as a joke? Were they being insulting? Why?)
510. K'aargs. K'aargs are ambiguously canonical guys with hilariously scary faces who apparently were conquered by a Nightsister (if you're not familiar with them, they're Dark Side-using Force wielders from the planet Dathomir, where normally only women use the Force) and then worshiped her as a goddess, as they're pretty primitive. Some rebelled against her.
And that's all there is to know, because there's almost nothing to know. It's also unlikely there will ever be anything else to know.
Rating: 3/5, out of pity for them and respect for their honestly hilarious faces. (Incidentally, they apparently originated in a French RPG magazine.)