In a large pitcher, combine the chilled brewed black tea, orange juice, pineapple juice, and lemonade.
Add the sugar and stir until fully dissolved. Taste and adjust sweetness if necessary.
Gently fold in the sliced strawberries, diced peaches, and diced pineapple.
Refrigerate the mixture for at least 1 hour to allow the flavors to meld.
Just before serving, add the lemon-lime soda to the pitcher and stir gently to combine.
Pour the cocktail into glasses filled with ice and garnish with fresh mint leaves if desired.