The Meyer Optik Domiplan 50/2.8 has 3 elements in 3 groups. It belongs to the Cooke triplet lens design.

https://allphotolenses.com/lenses/item/c_539.htmlY

You can get it for a low budget.  If you add a cheap teleconverter then you will get a similar bokeh effect like the Trioplan 100/2.8 although you have a 100/5.6 lens.

Set up with the teleconverter (sold by Wirgin Germany).

YouKnowItsTrue

Domiplan with teleleconverter 2x, open


 A great lens for creative shot!