It is now Robo 3T. But yes this is great software. You can even write functions to add to the collection. Simply create a function and open up a new search window. Add db.loadServerScripts() then your functions myfunciton('dateparam', 'another param') . You do need to use only ES5 and the db.collectionsNames are global.
You cannot do large collection queries if the server is remote i.e. ssh. So you still have to run a query that does things like update a million item collection on the actual server.
Siddarthan Sarumathi Pandian
Full Stack Dev at Agentdesks | Ex Hashnode | Ex Shippable | Ex Altair Engineering
Robomongo is open source.
You also have MongoDB compass from the Mongo folks themselves, but I don't think it's open source.