Hello Mumm02, can't find much on these, except when using Google Images, one can find those same images, and they source back to both Poland and Russia. Found a wholesale plant distributer in the Netherlands serving Europe (named Plant Estate), that lists those BigSam tm semps. Unusual is that they're using USDA hardiness which doesn't make sense for Europe. Not sure if Trade Mark laws in Europe follow same rules as USA. It is possible to go direct to Trade Mark naming so there's no way to tell if these are rebranded existing semp cultivars or direct-to-TM. In the USA, the true cultivar name (if there is one) is supposed to be on the plant label along with the TM name.
The name BigSam makes me wonder why that name. Could it be in reference to Big Sam, a very famous English football (soccer) player for 20 years and 25 years as coach and manager.
Partial view of a wholesale plant listing in the Netherlands