Ecuador: As you are no doubt already aware, a distinctive feature of the Ecuadorian use of the US dollar is the widespread acceptance and use of the "golden dollar" coins. The coins last a lot longer in circulation in Ecuador than banknotes, due to the equatorial climate that reduces used banknote paper to useless pulp within weeks. Any well-worn examples of golden dollars you might find in change or on the marketplace have likely seen service in Ecuador.
Example. The same is true of El Salvador, though apparently to a lesser extent. Criminal gangs in Colombia are known to have produced fake golden dollars for export into Ecuador.
Zimbabwe: following the collapse and abandonment of the Zimbabwean dollar, and the general reluctance of the people to trust any new form of money issued by the Zimbabwe government, a "basket of currencies" is legal tender in Zimbabwe, chief of which is the US dollar. This primarily denotes paper money, as coins are expensive to ship all the way to central Africa and until recently trade embargoes prevented the bulk shipment of
US coins. But any
US coins that arrive in Zimbabwe are gratefully accepted and placed in circulation.
East Timor: The official currency of East Timor is the US dollar. They have produced a series of "centavo" coins, struck in Portugal, where 1 centavo is on par with the cent, but
US coins freely circulate alongside their centavo equivalents, even thoguh the coins are generally of dissimilar sizes. East Timorese coins go all the way up to 200 centavos; as is the case in Ecuador, US $1 notes do not last long in circulation in the equatorial climate; unlike Ecuador, East Timor made no arrangements to import large quantities of golden dollar coins and they are never seen there.
Cambodia: Cambodia issues its own currency, the riel, but it is not widely trusted; US dollars are legal tender and are the primary circulating currency, especially in the big cities and the tourist traps like Angkor where dollar availability is high. The peacetime exchange rate of 4050 riel to the US dollar is awkward but stable, meaning that, while US dollar paper money is the dominant circulating currency for most transactions, small change is usually give out in riel notes. The 1994 series of coins issued by Cambodia are now rendered worthless by inflation, so
US coins would be the only coins in use; after decades of war and resultant inflation, the locals have largely forgotten how to use coins, but would probably accept
US coins if proffered, in preference to riel notes. Though not legal tender, Thailand coins and notes are also commonly used in the regions along the Thai border.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis