A useful list of which countries are welcoming foreign visitors (most!), and which still have restrictions.
Most countries require completion of a passenger information form, and ask for evidence of vaccination. Some require a negative Covid test. The FCDO website (www.gov.uk/foreign-travel-advice) has a clear summary of country entry requirements in more detail.
Fully open, no significant restrictions*
Argentina†, Belize†, Bolivia, Brazil, Colombia†, Costa Rica†, Cuba, Ecuador/Galapagos†, El Salvador†, Guatemala†, Guyana, Honduras, Nicaragua, Mexico†, Panama†, Paraguay, Peru†, Uruguay
*for fully vaccinated travellers
†no pre-arrival test required for vaccinated travellers
Open, but with some restrictions
Chile (arrival test), Venezuela (arrival test)