There are so many tonics, both industrial big brands and small batch products. I will try to steer you on the sea of tonics.
First the story of tonic.
Tonic water (or Indian tonic water) is a carbonated soft drink in which quinine is dissolved. Originally used as a prophylacticagainst malaria, tonic water usually now has a significantly lower quinine content and is consumed for its distinctive bitter flavour. It is often used in mixed drinks, particularly in gin and tonic.
The quinine was added to the drink as a prophylactic against malaria, since it was originally intended for consumption in tropical areas of South Asia and Africa, where the disease is endemic. Quinine powder was so bitter that British officials stationed in early 19th Century India and other tropical posts began mixing the powder with soda and sugar, and a basic tonic water was created. The first commercial tonic water was produced in 1858. The mixed drink gin and tonic also originated in British colonial India, when the British population would mix their medicinal quinine tonic with gin.
Picture from www.howtobeswell.com