After I looked around the board, I saw that the line of Wittelsbachs that ruled Holland, Zeeland and Hainaut in the 14th & 15th centuries doesn't really feature much, so here's a thread on them.
Jacqueline/Jakoba of Bavaria was the last of their line, and despite being married four times, she left no surviving issue (only a stillborn son with husband number 3). At her death the inheritance passed to the Burgundian Valois.
Her uncle, Johan III 'zonder Genade' (the Merciless (love medieval nicknames like this

)) was the successor to her father preferred by Sigmund, Holy Roman Emperor (due to the fact that Jacqueline was married to the French dauphin and then the nephew of the duke of Burgundy, the duke of Brabant)) and married to his niece (the duke of Brabant's stepmother). However, the marriage was likewise childless, and so in the 1430s, Valois-Burgundy inherited the lot.
Now, somewhere (I can't find it now) I read that Jacqueline had a legitimate brother born before her but died shortly after she was born. Which would make things interesting (although her uncle having a son that inherited both dad's claims to Holland, Zeeland and Hainaut and mom's claims to Luxemburg would be cool), or her having a son by her disaster of a second marriage who could inherit both her territories
plus Brabant etc, would likewise, but then it wouldn't really be a Wittelsbach Netherlands, now would it?
BTW: My idea revolved around a Netherlands divided between the house of Wittelsbach-Straubing (Jacqueline's branch), Valois-Burgundy and maybe the house of Luxemburg getting a punch in.
So, what if Willem VI of Bavaria-Holland (Jacqueline's father) or his brother, Johan III, had had surviving male issue?