Mixers can include lime juice, lemon juice, orange juice and spiced simple syrup, grenadine, tea, etc.

Besides the classic lime wheel, garnishes can include, for example, orange peel, star anise, thyme-elderflower, a slice of ginger, pink grapefruit and rosemary, cucumber, mint and black peppercorns, strawberry and basil, strawberry syrup, chillies and lime, etc.
Fruits such as kumquats or other citrus or cucumber can be muddled in it.
A gin and tonic can also be mixed with a sorbet.

Some gin-and-tonic inspired drinks also have champagne (e.g. the Parisian), vermouth and Campari (e.g. the Sbagliato-nic), vermouth and bitters (e.g. the Posh G&T), super smokey whiskey (e.g. the Ol' Smokey), peach liqueur and grapefruit bitters (e.g. the Tonic Delight), mint bitters and chocolate liqueur (e.g. the Guilty Pleasure), etc.
Mixers can include lime juice, lemon juice, orange juice and spiced simple syrup, grenadine, tea, etc.
Besides the classic lime wheel, garnishes can include, for example, orange peel, star anise, thyme-elderflower, a slice of ginger, pink grapefruit and rosemary, cucumber, mint and black peppercorns, strawberry and basil, strawberry syrup, chillies and lime, etc. Fruits such as kumquats or other citrus or cucumber can be muddled in it. A gin and tonic can also be mixed with a sorbet.
Some gin-and-tonic inspired drinks also have champagne (e.g. the Parisian), vermouth and Campari (e.g. the Sbagliato-nic), vermouth and bitters (e.g. the Posh G&T), super smokey whiskey (e.g. the Ol' Smokey), peach liqueur and grapefruit bitters (e.g. the Tonic Delight), mint bitters and chocolate liqueur (e.g. the Guilty Pleasure), etc.
Gin and tonic