The key word you said is "similar". There are a lot of similar programs but none that really work like Terrarium. You select your show, select your season, select your episode, servers load, pick one and away you go. All the other "similar" programs seem like you have to jump through hoops to get anything to play. Orders have to be signed in triplicate, sent in, sent back, queried, lost, found, subjected to public inquiry, lost again, and finally buried in soft peat for three months and recycled as firelighters (borrowed from the Hitchhikers Guide to the Galaxy).
This is the reason so many hang on to Terrarium; ease of use with no set up like one would have in Kodi. I love Kodi, but it is constant work to keep everything going where as Terrarium is basically install and play.