Maybe each race could have a proficiency that highlights their differences, which can replace either of the Class or General ones chosen at first level. If so, then one of these will allow any of the four core classes (i.e those normally reserved for humans) to be taken for whichever race the player wishes to play.
Rubbery Hide: always treated as wearing leather armour, but cannot gain benefit unless worn armour exceeds the base AC for leather.
Lord of Horses: experts at riding horses, especially into combat. When on horseback gain the equivalent of riding and combat trickery with respect to any one manoeuvre. Pick again to cover another manoeuvre.
Giant Strength: +1 to all damage rolls.
Duck & Cover: a talent learnt over the years of their prosecution, Goblins gain +1 to AC and +1 bonus to saving throws that depend on agility or cover (such as fireballs, arrow traps, and the like).
Natural Shine: skin radiates light equal to a torch, constantly. Can be switched off for no longer than a turn every three hours, due to the strain this puts on the creature.
Poisonous: can attempt to poison by a successful bite attack. Treat this as an unarmed attack (1d3 damage), that injects poison if a proficiency throw of 20+ is made. The victim must make a save versus poison or take double damage. This can be chosen multiple times, lowering the proficiency throw target and increasing the damage by one step (i.e. pick twice, 16+ for x 3 damage; three times for 12+ and quadruple damage, and so forth).