Because of the location and story lines established for the Petronia Game Setting, there are restrictions on some races while others are not allowed at all.
Allowed races:
Dwarf
Half-elf
Human
Gnome
Restricted races require DM permission to play:
Dryad - tree spirits with several play restrictions.
Elf - limited to sea elves, which could restrict play.
Halfling - the nearest enclave is very far away.
Half-orc - most are slaves or runaways.
Orc - most are slaves or runaways.
Goblin - most are slaves or runaways.
Sprite - small fey creatures with several play restrictions.
Tiefling - widely feared and reviled.
Forbidden races:
Dragonborn - this race doesn't exist in Nolaria.
Giant - players are not allowed to play giants of any kind, even Half-giants.
Additional consideration and notes:
Dwarves and their old culture play a central role in the Petronia game setting. Furthermore, most dwarves locally are held as slaves. Emancipated dwarves exist, but they are VERY rare. Free born dwarves are often assumed to be runaways and are arrested for return to slavery. Playing a dwarf will require building a solid background that enables play and fits into the story arc.
Various kinds of elver exists in Nolaria. The closest settlement is on Jacinth Island, off the coast of Petronia. Jacinth is home to a colony of sea elves. While it is possible to play a sea elf, they naturally prefer being on or near the ocean, which could restrict or hamper play. There are also colonies of sylvan elves, though further away. Speak with the DM if you want to play an elf of this variety.
Drayads are female tree spirits. With permission, you could play a dryad, though there are restrictions on how far you wander away from your tree and what might happen to it while you are gone. Dryads are sufficient rare that they will not be taken for a slave, but neither will they be accepted in human society.
Halflings (Hobbits) are not native to Norberg. In GY 1662, an enclave of Halflings was established in the Barony of Azure in the Kingdom of Norberg by Susan Carter. Since Azure is about 1200 miles away from Petronia, it is extremely unlikely that a halfling wandered into the local area. However, if you can come up with a convincing story, the DM will consider it.
All orcs and half-orcs are slaves. Such beings found wandering about are assumed to be runaways and are subject to immediate arrest, subjugation, or destruction. That said, there are orcs and half-orcs living locally. Most of these are runaway slaves. Given the illegal nature of runaway slaves, the question to a player who wants to play a character of this race is how you might convince other characters to allow you to adventure with them.
Most goblins are slaves, but there are some free goblins in Petronia and Mernia. Unless locally know, officials will assume goblins are also runaway slaves. It is up to them to prove it - which can be difficult at times. There are one or two well-known goblin families who are merchants, but these groups have fallen on hard times and are no longer seen much in public.
Sprites are small, fey creatures who live in remote, secluded colonies. Most have no desire to ever venture beyond the safety of their homes, but occasionally an adventurous sprite will wander off. Most humans will consider sprites to be unnatural, but since they are occasionally taken as familiars they are accepted (with suspicion). Due to their small size, there are some serious restrictions on starting ability scores.
A tiefling is the offspring of a the mating of a human and a demon (or devil), usually (but not always) the result of rape. Such children randomly inherit aspects (and abilities) of their infernal parent. Unless disguised, tieflings are not accepted in human society. They are subject to persecution and possible death. Elves especially do not get along with tieflings. Humans will assume they are evil, which means that neutral or evil humans can at least work with them, though trust is unlikely.