These are races that are so rare or powerful that explicit GM permission is needed for a player to use one. The very existence of at least one of these races, Golemforged, changes the whole tenor of the campaign setting.
That is not to say these races shouldn't be allowed. But both GMs and players should be prepared for the repercussions of one of these races wandering the world.
Orcs are a rare and dying breed. War hasn't driven them to the brink of destruction. Peace has. Orcs rose to the moment, and helped humanity save what could be saved during the Shambling. Afterward, humanity accepted and embraced orcs in a way they never had before.
This intermingling has left little room for full-blooded orcs. Most have accepted this change and live happily side-by-side with humans—intermarrying as they will. Some orcs, however cling to the old ways. They don't hate humanity, but they are fiercely proud of orc heritage and see the intermingling as a loss for orcs as a whole.
Small pockets of orcs gather around in druid groves and exchange stories of the old ways. Verbal history has always held a strong place in orc society, so modern orc shamans tell many stories of the past, though they often talk of past conflicts with humans as being born from a desire to be accepted or from misunderstandings and mistrust.
At least one orc leader, Grakthar in the city of Kytark, hears something different in the stories, though. He is secretly gathering orcs together to take, as he sees it, their rightful place atop the "weakling humans".
This is probably the least disruptive of the non-standard races in terms of story. The rules of your particular game will dictate how disruptive the power of orcs is over the other races.
At the beginning of the Age of Shambles, people looked to many different areas for comfort, power, and assurances of another day. Some of those people called upon low, dark powers. These powers now touch the world more deeply.
"Demonbred" is a general term for all characters whose race involves darker, demonic heritage. These PCs would be reviled and hated, not because of their strange appearance, as much as because some would blame them for the Shambling. Many would see demon horns as a mark of magic, which would lead to many difficulties.
A demonbred character can come from a cursed family, a true-breeding off-shoot of demonbred, or, perhaps, made a personal deal with a dark force for increased power.
The Old Gods have left the world, or so many believe. If angelbred walk the world of Vernlarum, then they are the last remaining sign of deific presence. Arkers and priests of the Old Gods alike would be drawn to an angelbred character seeking insight, wisdom, and assurances of their beliefs. The angelbred character, likely, has no more insight than they do.
"Angelbred" is a term for any character whose race is celestial in nature. These characters would struggle with people flocking to them for answers and knowledge they don't have. When an angelbred's answers fail to meet the expectations of those asking the question, some will become angry and assume the angelbred character is withholding wisdom capriciously or spitefully.
An angelbred character might come from a blessed family, a true-breeding family of left-behind celestials, or the individual might have been blessed by some unknown force for its own ends.
Dragons exist in Vernlarum. Their power and might are well known , and feared, by people at large. A half-dragon, or any dragonman, might be met with fear and suspicion. Or he might be met with gifts and supplications, if people believe he is a harbinger of full dragons.
If a GM wishes to make dragonkind characters more integrated into the world, they can be a known, if rare, race who mostly reside in the city of Lazon—an out of the way city known to be inhabited by a number of dragons. Perhaps half-dragons are their servitors and ambassadors to the world.
No race would be more problematic in Age of Shambles than Golemforged, and GMs should carefully discuss this issue with an entire table to see if they want to share a game with Golemforged characters.
A "Golemforged" character is any character with a race that is in part, or entirety, golem or even golem-esque. Sentient trees would be as problematic as more robot looking creatures.
Golems destroyed an Age and prevent the people of Vernlarum from ever establishing a stable home anywhere except on the back of one. They destroyed the ecosystem and turned a lush, green land into the Wastes. Golems are hated and feared. A humanoid, sentient golem would struggle to not be worshipped or torn to pieces depending upon the mood and mindset of the people encountered.
One possibility would be to have an entire party of golemforged who awaken in ruins castoffs of Ruiner experiments in the previous Age. Perhaps all they want to do is explore the world and find their niche in it. Perhaps, somewhere, there is a facility that is making these Golemforged, and they wish to establish peaceable trade with the rest of the world. A campaign focused on story, political intrigue, and diplomacy would be a good match for this storyline.
There are other races which various rule sets make as playable character races—gnolls, pixies, minotaurs, or the like. These races mostly have a place in the world of Varnlarum. GMs will be best at helping a player find the right balance at their individual tables.
The people of Vernlarum are complete strangers to the idea of gnoll traders or minotaur bodyguards, but these instances are rare enough that any representative of these more savage races will be remarked up and face some level of discrimination.
People mostly try to just make it through each day, though, and if a gnoll returns a lost child or a minotaur stops a band of raiders, people can forgive and overlook much. Of course, the next time the city is raided by a vicious band of gnolls, that mood might change again.