I need to correct myself; There are just Sprite Based Additions (Lines, Circles made out of Lines of Sprites, Rectangle(filled and empty)) but no Polygons or other kinds of filled geometric shapes.
I have implemented it myself by now; probably not the best way i could do it but it is fast enough atm.
(I used a class named Poly which contains Vertices;
this class is contained in different Lists (one for Lines, one for Vertices etc);
These Lists are then Emptied at the beginning (Begin():function)
and drawn at the end(End():function) <- pretty simple eh?
the Lists can then contain all different kinds of polygonal forms even those i didn't prepare beforehand)
Source: http://pastebin.com/PHBuS2We | Needs Monogame.Extended for the SetBF:function()! Remove the Function and the usage Reference then you should be able to use it w/o Monogame Ex
This ^ uses Lists and not just Arrays otherwise it would not be dynamically enough to work this way;
The Problem is that Resizing the Array would take really a massive amount of time wich is wastet in each Draw-Call.
If somebody has a neat Idea to improve this(There are many Shapes not implemented as of right now for example also the speed is not the best it could be so); Please feel free to do so and maybe share it with us.