These Insignias are "free give aways" diplomacy necklace items from the cities to adventurers of at least adventuring level 10. Each has three presences, with a +25 magnitude to each. Click to see the clothing values on each. Note that the Dwarf City Registrar is now on the current build, and is giving out the Dwarf Insignia (the value has been added to the appropriate article).
The Town Insignias are items given by city faction NPCs. Once you equip it, you'll get rewards from killing mobs. These rewards will allow you to get racial mounts, racial armor and utilities such as mana or health potions.