The best replacement for headspace is purge and trap.

The best alternatives to headspace are rated as following:
★★★★★  purge and trap
★★★★★  buddhify
★★★★  yoast
★★  spme
★  thermal desorption

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

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



Google Trends

Scale is based on the average worldwide traffic of headspace in all years. Click on graph for more.
headspace
purge and trap
buddhify