The best replacement for underground is mainstream.

The best alternatives to underground are rated as following:
★★★★★  mainstream
★★  mainstream hip hop
★★  underground
★★  overhead
★★  tuk creepers
★★  mainstream music
★  under ground
★  accuweather
★  overhead power lines
★  heathrow express
★  overhead service
★  tuk
★  surface mining
★  mainstream rap
  london transport
  open pit mining
  most wanted
  weather channel
  christina aguilera
  midnight club
  juiced

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

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



Google Trends

Scale is based on the average worldwide traffic of underground in all years. Click on graph for more.
underground
mainstream
mainstream hip hop