Best drugs (besides benzos) to sleep after 4f-mph?

Currently on probation so I need to not pop hot on any UAs. OTC or illegal, what do you guys find helps you sleep after 4fmph that won't show up if I get dropped?

Side note I got a lotta GHB, does that work for this?

Edit: Feels like zopiclone is the winner, where y'all land on that?