My maternal aunt is a Nomad, and blood type B. She physically fits that Nomad profile. What is interesting is that on my maternal side of the family, there is actually some true nomadic DNA. We have some Kalmyk ancestry---a nomadic asian tribe that has lived in the Russian steps around the Caspian sea. I looked up blood types by ethnic origin---ethnic groups all over the globe. The ethnic group with the highest percentage of Type B blood (as compared to the other blood types ), to my amazement, was the Kalmyk ethnic group. (I believe my grandfather and his mother were the carriers of type B in the family. Great-grandmother had the eurasian facial features, and grandfather and his brothers had the olive skin and dark eyes, black hair.)

I thought it interesting that one's ethnic origin can be so closely tied to one's genotype and blood type.

Yes, very interesting.  

I’ve often tried to speculate where all the blood types in my family line came from.  

Quoted from RedLilac

I’ve often tried to speculate where all the blood types in my family line came from.  

so do I  

Well considering that some of my ancestors came from the Danelaw (scottish lowlands) I have a good idea.

I've always been called the "gitan" or gypsy in my family...but don't know of any B blood...only O's and A's.
On the other hand, my Dad's line, O-, dates back to the Basques in Navarre (France/Spain) and my Mom's line is mainly from southwestern France where they have  many gypsy grape pickers.....

gulfcoastguy---Danelaw from the Danish vikings that settled central Britain. Weren't the vikings a  nomadic bunch? They made their way throughout much of Europe between about 800A.D. to 1000A.D. It's great that you have been able to trace your family that far back.

cajun---that is very interesting that you have a Basque and French gypsy background. The Basques have always been a mystery---no anthropologist knows the origin of the Basques; and their language is not related to any other Indo-European language. Gypsies were nomadic, yes?

Bien sur! The gypsies were/are nomadic. Presently, there are Portuguese gypsies that work during the grape harvest in southern France.

My Dad is so fortunate (as am I )to be able to trace a direct paternal line to the 15th century House of Bourbon in Navarre (which exists no longer but is the Basque territory that covers part of northern Spain and southwestern France in the Pyrenees)
Our ancestor is the brother of the Saint Francis Xavier. He fled to England , married, his son came to America and his grandson, Thomas Sevier(name was changed..Xavier-Sevier.. for pronunciation) became the first governor of Tennessee.

My Dad is also the common Basque blood type O, RH-, and I think he is an explorer genotype.