Anac - Agência Nacional de Aviação Civil (National Civil Aviation Agency): The regulatory agency responsible for the standardization and enforcement of civil aviation legislation by airlines and airport operators. 
Contact: https://www.anac.gov.br/fale-com-a-anac

SAC - Secretaria de Aviação Civil da Presidência da República (Civil Aviation Secretariat of the Presidency of the Republic). 
Contact: https://www.gov.br/ouvidorias/pt-br/cidadao/lista-de-ouvidorias/adm_direta/secretaria-de-aviacao-civil-sac 

Decea - Departamento de Controle do Espaço Aéreo / Comando da Aeronáutica (Department of Airspace Control / Air Force Command): The agency responsible for, among other things, air traffic control in Brazil. 
Contact: www.decea.gov.br

Departamento de Polícia Federal (Federal Police Department): The agency responsible for immigration/emigration control and security in restricted areas of airports. 
Contact: www.dpf.gov.br

Vigiagro - Vigilância Agropecuária Internacional (International Agricultural Surveillance): A sector of the Ministry of Agriculture and Livestock, responsible for international agricultural surveillance. 
Contact: https://www.gov.br/agricultura/pt-br/assuntos/vigilancia-agropecuaria

Ministério da Agricultura e Pecuária (Ministry of Agriculture and Livestock). 
Contact: https://www.gov.br/agricultura/pt-br

Bacen - Banco Central do Brasil (Central Bank of Brazil): Information for travelers regarding currency exchange. 
Contact: https://www.bcb.gov.br/en 

Ibama - Instituto do Meio Ambiente e dos Recursos Naturais Renováveis (Brazilian Institute of Environment and Renewable Natural Resources).
Contact: www.ibama.gov.br