Final answer:
The most common fruit used to garnish tequila drinks is lime, which adds acidity and enhances the drink's flavor profile.
Step-by-step explanation:
When it comes to garnishing tequila drinks, the most commonly used fruit is the lime. This citrus fruit not only adds a touch of acidity and freshness to balance the sharpness of the tequila but also enhances the flavor profile. While the reference to guacamole's ingredients such as avocados, lemon juice, and tomatoes provides a culinary context, the fruit we're focusing on for tequila drinks is the lime, chosen for its ability to complement the drink's flavor without overpowering it. Slices or wedges of lime are often placed on the rim of the glass or dropped into the drink for an extra burst of flavor.