With these ideas, players from kitchen-sink-fantasy systems who are leery of OSR systems without tieflings© and other exotic PCs can play characters with a similar vibe without breaking your world-building. You can use the ability bonuses and skills of the regular ancestry, perhaps altered slightly.

Sylvan Elves

These are wild tribes that each have a totem animal and take on traits of it, such as small versions of the horns of a wild sheep or goat, tusks of a wild boar, a tail, the animal’s coloration (fine fur), etc.

In middle age, the traits become more pronounced, and many elderly tribe members eventually make a sudden, rapid, and complete transformation and take to the wilderness for their final days.

Cursed Ones

These are of a family (of any ancestry) that has been marked by a powerful witch or fiend with a generational curse. They may have skin of an unusual color, a tail, claws, small horns, etc. or even resemble a goblin or similar humanoid.

Widely mistrusted, they each have a secret goal to lift the family curse that bodes ill for others:

• As long as the bell tower of Incor city stands…
• As long as Arduus, the Plague Mace, remains idle in the Patriarch’s Palace…
• As long as the great warship Zephyr Wind sails…
• As long as no monstrous beast sets foot in the bailey of Othyar Castle…