The tracks usually thought of by fans as the best on the soundtrack are Debris, Don't Let Go, Aningaaq, Tiangong, Shenzou and Gravity.
Phenibut was first synthesized by the Russians during the 1960s to relieve tension, anxiety and fear, according to one 2001 study. (It is still prescribed there for these purposes today.) Phenibut is a nootropic or smart drug, a supplement that purports to enhance cognitive performance by increasing memory and attention.
If phenibut is helping you, then keep using it but exercise caution (use twice per week, not three times per week). Ask your doctor for gabapentin or pregabalin. They can help with withdrawal for phenibut so that if you ever do mess up and go four days on, you'll have something to bring you easily back to baseline.