Compton is described as 'compositor for X, and a fork of xcompmgr-dana' and is an app in the OS & Utilities category. There are three alternatives to Compton for Linux, BSD and FreeBSD. The best alternative is picom, which is both free and Open Source. Other great apps like Compton are Xcompmgr (Free, Open Source) and Wayfire (Free, Open Source).
Picom is a standalone compositor for Xorg, suitable for use with window managers that do not provide compositing. Picom is a fork of compton, which is a fork of xcompmgr-dana, which in turn is a fork of xcompmgr.
Xcompmgr is a simple composite manager capable of rendering drop shadows and primitive window transparency. Designed solely as a proof-of-concept, Xcompmgr is a lightweight alternative to Compiz and similar composite managers.