The best replacement for aphids is spider mites.

The best alternatives to aphids are rated as following:
★★★★★  spider mites
★★★  fruit flies
★★  scale
★★  mites
★★  gnats
★★  white flies
★  thrips
★  fungus gnats
★  mealy bugs
★  ladybugs
★  springtails
★  soil mites
★  scales
★  mealybugs
  white fly
  ladybird
  whiteflies

Your alternative for aphids is not listed? Suggest!
Speaking about aphids, one probably shouldn't forget about ladybugs.

Other search terms related to aphids and their ratings are:
★★★★★ ladybugs
You have in mind a companion for aphids and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of aphids in all years. Click on graph for more.
aphids
spider mites
fruit flies