Verbotron by Max for Cats is great Max for Live addition to your collection of reverbs. It uses the original Gigaverb algorithm by Juhana Sadeharju which is also known as "Gverb" in Audacity. It also features a handy visual representation of the reverb parameters. Verbotron requires Live 9 and Max for Live 7 and comes in a self-installing Live Pack that contains 9 presets. More info.
This is a free download. Simply add a "0" into the price field. Unless you would like to donate something which is always appreciated.