Natural predators such as ladybirds 🐞, hover fly larvae, lacewing larvae and parasitic wasps can be attracted to your garden or bought online/in stores.
There are insecticides for aphid colonies but this should be avoided as it will not work on plants that cannot be completely covered in the insecticide such as larger plants/trees & flowering plants as you could kill beneficial pollinating insects. 🐝
Taken by myself. (Click image to view in high quality)