A complete and up-to-date searchable list of all EU4 faction IDs.
Factions represent powerful and influential groups within the country. Each faction has an influence rating associated with it, and the faction with the highest influence will give a set of bonuses (and penalties) to the country.
Flagships are unique ships that give special bonuses to all ships in fleet with them. A nation may only have one flagship of their own (not counting captured flagship which lose their bonuses but keep their name and icon). A flagship can be any combat ship type (non-transport).