What are fabled species? I've seen people talk about them, but I'm not clear on which species that refers to. I assumed it meant something like Ny'venes or Puffs? Second, what kind of pricing is good for a non-themed/project, un-tagged pet? Right now, I have this guy up for 700g. Is this too much? Too little? Any advice would be welcome!

Fabled species are:
Ryori (found during Fall Fest)
Griffi (found during Winter Fest)
Aeridini (Spring Fest)
Lighira (Summer Fest)
Nephini (exceptionally rare, found in the Astryl's Vale zones and all Fest zones)
Ny'vene (from the Ny'vene shop in Ethernia's Arena)

Puffadores could be considered a sort of borderline, in that they can only be obtained from the Puffadore pet shop in Ethernia, but are not a true Fabled species.
(if you go to the Generator and click 'View List of Species', Fabled species have... well... 'Fabled Species' written below the species name)

The difference between Fabled pets and regular pets is that they have higher base stats.
A regular sylesti that's wild-caught has an average stat of
- around 11 points for Str/Int/Dex/Agi
- typically 100-130 HP
- a base mana correlating with their stars (wild pets with 1 star have 60, 2=80, 3=100, 4=120).

A wild-caught Fabled pet will have
- average 20/21 in Str/Int/Dex/Agi
- typically 130-150 HP
- base mana 20 points higher than the equivalent regular (but still cap at 120 points; 1=80, 2=100, 3=120, 4=120)

Pricing is a very difficult thing, but I reckon you could probably sell that puff you have for 700 for a bit more, but that's just because I think he's pretty.

People are willing to buy puffadore for 3-10k, honestly. I sell mine at 3k and they sell, people also sell them at 6k pretty well.

Ahh I see. Thanks!

And just an added note, while puffs aren't labeled as fabled if there is an event where an egg has a chance at hatching a fabled themed pet or you have a chance at a fabled essence/pet making component, puffs will be included. So, the admins lump them into the fabled species for those kind of events.