Fun fact: There is no default country, that allows all policies.
You can make country, that has all prereqs.
Such country would have German tax, Canadian North Passage, Korean NK situation, British monarchy and few more stuff.
_prereq_land_border - Border Wall
Germany, USA, Spain, South Korea, France, Canada
No UK, Australia
_prereq_has_coast - Border Navy
Germany, USA, UK, Spain, South Korea, France, Canada, Australia
_prereq_sovereign_currency - Capital Controls, Helicopter Money, Quantitative Easing
USA, UK, South Korea, Canada, Australia
No Germany, Spain, France
_prereq_nuclear_tech - Nuclear Fission
Germany, USA, UK, Spain, South Korea, France, Canada
_prereq_germany - Solidarity Tax
No other countries