This is a useful guide to the fragmentation and atomisation of the Labour Party: http://www.newstatesman.com/politics/staggers/2015/10/labour-s-warring-factions-who-do-they-include-and-what-are-they-fighting
I had never heard of Labour for the Common Good and Labour Together, and only had a hazy awareness of Labour First.
And note that Momentum is included in the article (by Anoosh Chakelion in the New Statesman) as if it is an entirely respectable organisation.
No Tribune Mr Chakelian?
No Fabian Society? No Centre for Labour and Social Studies (Class)? No Demos?
No Labour Relaxed (championing the Filthy Rich since 1997)?
No Granita Group (advocating an entirely pragmatic system of allocating positions of power using the highly respected Buggins Turn formula)?
No Axelrod Axis (putting PR at the heart of Labour, where it has always belonged).