Reptilians and their kin

Kobolds are a ancient race that is as old as the gnomish race.
While originally an adavanced species with many a city and metropolis, events that have occured over hundreds of thousands of years reduced them to a more poor a simple method of survival.
Without their cities, mines, trade centers, and allies, the kobolds species have resorted to the following: Raiding civilizations they hate (primarily gnomes, goblinoids, and occasionally halflings), Cannibalism of their own reptilian kind as well as on humanoid kind, Alliances with beings they hate, and Trapmastery.
Kobolds speak common and draconic, but if you are a gnome, goblinoid, or halfling, you likely will not even get a chance to speak.
Lizardfolk are a ancient race that is very old but very primitive.
They have existed for as long as the humanoid races, but primarily worship nature deities as well as deities related to elements. They are known to speak both common, draconic, as well as their own language. Because of their primitive civilization, they have often come in conflict with humans, who view them with disgust. Lizardfolk, for instance, care more for the survival for their species as a whole than for any single individual, and often due not have the mental faculties to pay attention to morality on a constant basis. As such, Lizardfolk will often take what they need so long as the object is not being used, and will often discard things they have no use for, in spite of its importance to others. They have been known not only to cannibalize their reptilian kind, but also their own species, as well as humanoids. In fact, it is not unusual for a lizardman to not understand the anger of a humanoid over the loss of their companion's corpse. Lizardfolk finally have adepted exceptionally well to jungles, forests, swamps, marsh, lakes, and sea regions. Lizardfolk take full advantage of creating anything they can from bone, scale, hide, and plants. They also intelligently fortify their villages against local threats as well as positioning them in places where safety is easily accessed as well as food resources. They also can hold their breaths underwater for several hours before needing to return for air.
Dragonkin are humanoid beings mixed with the blood of dragons, but due to their combination of so many humanoid and draconic ancestors of different types they have formed their own species and culture, which is quite rich and diverse, combining the best of dwarven and elven culture, while maintaining draconic superiority.
Troglodytes are lizardfolk in appearence but are adapted for life in mountains, hills, caves, and the underdark. These beings have all the traits of lizardfolk, except for the fact they are intelligent enough to comprehend fully moralty and law, yet, they completely disregard it. Troglodytes are evil beings in nature to everything except reptilians, and they often prey on dwarves, duegar, elves, drow, and any other humanoid and goblinoid in their region close in proximity. Troglodytes appear to have some form of advanced religious system, but little is known of it.