Offshore is common term. Its collectively all those small countries which have minuscule corporate tax, zero financial rules and refusal to cooperate with big countries about financial tax evasion. Basically everyone from Ireland, Switzerland (sorry guys, just business) to Bahamas and Panama (and ban flags of convenience while we are at it). Definitely all countries refusing to disclose financial records for international law enforcement.

If I were planning such effort, I would propose do bans in waves, with multiyear intervals. E.g. ban of top10 worst offender countries - Cayman islands, British Virgin islands, Seychelles, etc. Then make a list of 10 next and warn them that they have 2-3 years to adjust or be banned too. Rinse and repeat.