What is the best MongoDB client for iPad
Any client for MongoDB from AppStore should work equally well for derived products, mLab, MongoDB Altas, some custom servers, etc.

Commercial Clients with a Free Option


MongoLime - Free version with one MongoDB connection


Commercial Clients


MongoMonitor - not free
MongoFly - not free


I suggest you take a look at MongoLime since I believe it the best (it has a built-in SSH tunnel), and I can get my job done with it.