iSerenity is described as 'website that features a few environmental sounds (like 'Rain', 'Wind Chimes', 'Birds', 'Waterfall', 'Ocean', and so on)'. There are more than 25 alternatives to iSerenity, not only websites but also apps for a variety of platforms, including iPhone, Android, iPad, Android Tablet and Windows. The best alternative is A Soft Murmur, which is free. Other great sites and apps similar to iSerenity are Tide (by Moreless) (Free), Noizio (Paid), Rainy Mood (Free) and Pzizz (Freemium).
ANoise is a minimal ambient noise player to help you focus on your productivity! Just open the Ubuntu sound indicator and choose your noise: Coffee Shop | Fire | Forest | Night | Rain | Sea | Storm | Wind