17" faience figurines whose mark is this: impressed LB

I think they are faience. Auction manager says they are Limbach I dont see it in the database I use so I dont know..

 

There's a Limbach LB mark mentioned in the Handbook of Marks on Pottery & Porcelain, but it doesn't look like yours...

 

If it's Limbach, it would be porcelain. I don't know if it is Limbach.

From https://www.worthpoint.com/dictionary/p/ceramics/ce-germany/limbach-porcelain:
Initially, the Limbach marks were initials, the letter "L" in a script font, variations of "LB" in monogram,and two crossed mirrored letter Ls sometimes over an asterisk. In 1788, the cloverleaf mark was introduced at the Limbach factory. It was also adopted by the Kloster Veilsdorf, Breitenbach, and Ilmenau factories. The numerous marks with crowns included different crown styles, such as "1772," a script font "L" inside a cloverleaf and a script "Limbach" below, or a mark minus the word “Limbach” with initials within a triangle added to the crown and cloverleaf Additional crown marks featured a crown and a cloverleaf within a shield with “1772” over “LIMBACH” in all caps below, a crown and cloverleaf with “72” or “1772” and “LIMBACH” crisscrossed in between the crown and cloverleaf. The words "Breitenbach et Limbach" with "Grube" underneath in a script font were also a mark the factory used. Marks were painted in blue and lilac.

 

Could it be the Erfurt region listed here:

https://www.beerstein.net/articles/s9606a.htm

 

These look like porcelain to me?

 

Yes.