I am always interested in knowing wtf the national ideas are for new nations. To save other people some time I did some digging in the files, here is a list of the new ones added/changed in Beyond the Pale.

Tír na Celtigh (I assume)
start =
infantry_power = 0.2
land_morale = 0.1
bonus =
army_tradition = 1
celts_survival =
war_exhaustion = -0.05
celts_six_nations =
idea_cost = -0.1
celts_monastic_schools =
technology_cost = -0.05
celts_soldiers =
discipline = 0.05
celts_memory =
core_creation = -0.25
celts_illuminated_manuscripts =
prestige = 1
celts_resettle =
culture_conversion_cost = -0.25

Kingdom of Ireland (Anglo-Irish)

KOI_ideas =
start =
global_tax_modifier = 0.15
production_efficiency = 0.1
bonus =
stability_cost_modifier = -0.1
koi_baptism_by_fire =
army_tradition = 0.25
discipline = 0.025
koi_mixed_heritage =
accepted_culture_threshold = -0.25
koi_parliament_ireland =
advisor_cost = -0.15
koi_trim_castle =
defensiveness = 0.20
koi_urban_culture =
build_power_cost = -0.1
build_cost = -0.1
koi_bill_of_rights =
global_unrest = -2
koi_anglo_rapprochement =
relations_decay_of_me = 0.1
diplomatic_upkeep = 1

Not sure about High Kingship, I think it uses the same modified Irish Ideas as any of the Clanns. They all seem very competative without being too OP. I think thats all of them, I am using the Broken World mod w/ Beyond the Pale support and having a lot of fun : )