Alternate Possible Female Monarchs or Usurped Heiresses
Poland
OTL
Jadwiga of Anjou
Anna Jagiellonian
Possible other Queen Regnants in close proximity to succession/de jure successors
Elisabeth Richeza
I think she could lead Poland to be ruled by Habsburgs or a Polish-German Union, by the Premyslids or a continuation of the House of Piast, she married a Habsburg and a Premyslid, she did things that the Polish nobility prevented Jadwiga to do so.
Elisabeth of Pomerania
Her brother is more likely impotent or sterile, if her brother becomes King - she is the heiress once her brother dies since any of the issue or heir his wife could bear have a doubtful paternity (her namesakes Isabella of Castille and Elisabeth Farnese took advantage of their brother's lack of secure heir, due to his sterility/impotence), she could be the wife of Louis I of Hungary to secure his succession, her OTL husband Charles IV could use her or her brother as a pretext to start a war of succession.
Mary of Hungary
The first choice to succeed the throne but was prevented from succeeding due to her fiancé.
England
OTL
Queen Victoria
Elisabeth I
Elisabeth II
Anne I
Queen Mary I
Jane Grey
Possible other Queen Regnants
Philippa of Clarence
The mother of the presumed heir of Richard II.
Charlotte of Wales
The presumed alternative to Victoria- the first choice to succeed, she died in Childbirth in OTL.
Eleanor of Brittany
Locked up and imprisoned in OTL.
Arabella Stuart
In OTL, Imprisoned due to marrying without permission.
Elisabeth of York
She did became the queen consort.. oh well...
France
Possible Queen Regnants
Joan II of Navarre
She was prevented in succeeding the French throne due to the Salic law.
Isabelle Claire Eugenie of Spain
She is a good candidate for marriage with Henry of Navarre, he married her Aunt in OTL.
Poland
OTL
Jadwiga of Anjou
Anna Jagiellonian
Possible other Queen Regnants in close proximity to succession/de jure successors
Elisabeth Richeza
I think she could lead Poland to be ruled by Habsburgs or a Polish-German Union, by the Premyslids or a continuation of the House of Piast, she married a Habsburg and a Premyslid, she did things that the Polish nobility prevented Jadwiga to do so.
Elisabeth of Pomerania
Her brother is more likely impotent or sterile, if her brother becomes King - she is the heiress once her brother dies since any of the issue or heir his wife could bear have a doubtful paternity (her namesakes Isabella of Castille and Elisabeth Farnese took advantage of their brother's lack of secure heir, due to his sterility/impotence), she could be the wife of Louis I of Hungary to secure his succession, her OTL husband Charles IV could use her or her brother as a pretext to start a war of succession.
Mary of Hungary
The first choice to succeed the throne but was prevented from succeeding due to her fiancé.
England
OTL
Queen Victoria
Elisabeth I
Elisabeth II
Anne I
Queen Mary I
Jane Grey
Possible other Queen Regnants
Philippa of Clarence
The mother of the presumed heir of Richard II.
Charlotte of Wales
The presumed alternative to Victoria- the first choice to succeed, she died in Childbirth in OTL.
Eleanor of Brittany
Locked up and imprisoned in OTL.
Arabella Stuart
In OTL, Imprisoned due to marrying without permission.
Elisabeth of York
She did became the queen consort.. oh well...
France
Possible Queen Regnants
Joan II of Navarre
She was prevented in succeeding the French throne due to the Salic law.
Isabelle Claire Eugenie of Spain
She is a good candidate for marriage with Henry of Navarre, he married her Aunt in OTL.