The Brexit Mod
A mod about the OG brexit and English/British flavor. Enjoy.
Anglicanism
You can become separate from the Pope and make the Church of England a vassal of the English king. Anglicanism has got crusades disabled and autocephaly.
The United Kingdom
If you control all the four kingdoms in the British Isles you can form the United Kingdom. Enacting this decision enables more minor ones like: Forming the Crown Dependency of Man, integrating Cornwall into England and integrating France into the UK.
Parliament (Conclave)
Before 1215 you can issue the Magna Carta to enable the Parliament mechanics. These mechanics are automatically enabled after 1215. Parliament has MPs, elected through a hidden event, and Lords, appointed by the King.