In the large pitcher, combine the blackberries, orange slices, and lemon slices.
Use a muddler or spoon to gently muddle the fruits, releasing their juices and flavors.
Pour in the red wine and brandy, followed by the honey or agave syrup. Stir to combine.
Add the orange juice and give it another gentle stir.
Allow the sangria to chill in the refrigerator for at least 2 hours, allowing the flavors to meld together.
When serving, fill wine glasses with ice cubes and pour the chilled sangria over the ice, filling each glass about two-thirds full.
For a touch of fizz, top off the glasses with a splash of club soda.
Garnish with additional blackberries and citrus slices if desired.