September 24, 2020 Updates:

Costa Rica: ("at most 48 hours")
Hawaii (?)
Ecuador (deletes 1st sentence from before)


September 25, 2020 Updates:

Hong Kong (adds: (or who have been to a high-risk country as defined by the government of Hong Kong))
Guam (defines how/where negative test result takers can finish quarantine)
Brasil (see below)

Is: Travelers entering Brazil who are staying for a short time (90 days or less) must present proof of medical insurance coverage in Portuguese, English or Spanish in order to board their flight. Insurance must be valid in Brazil for the duration of the stay and include at least $6,000 (30,000 Brazilian real) of coverage.

Was: Travelers entering Brazil who are staying for a short time (90 days or less) must present proof of medical insurance coverage that is valid in Brazil for the duration of their stay in order to board their flight.

David