I'd love to be able to tell you there are defined lines between the types but there are not. I asked because some have a notion of a particular type (Texas, say) and a particular conception of what they are looking for, so my next question is always for specifics. In most areas a variety are made, pork, beef, pork and beef mixed. This occurs within areas and between them. All beef tends to be the case in many spots in Texas but I have had mixed meat sausages there too. Many Texas hot links are not at all hot. The ones in La tend to be hot if called 'hot'.
Are you looking to make your own as links or patties or...?