Global Universe Metadata
This sample query can be used to fetch global values such as address for TransactionRouter, DepositContract and dETH and counters for registered validators vs number of created houses etc.  
{
  universeGlobalValues {
    TransactionRouter
    DepositContract
    dETH
    numberOfRegisteredValidators
    numberOfKnots
    numberOfStakeHouses
  }
}
Here's the sample output:
{
  "data": {
    "universeGlobalValues": [
      {
        "TransactionRouter": "0xc4b44383c15e4afed9845393b215a75d44d3d24b",
        "DepositContract": "0xff50ed3d0ec03ac01d4c79aad74928bff48a7b2b",
        "dETH": "0x506c2b850d519065a4005b04b9ceed946a64cb6f",
        "numberOfRegisteredValidators": "145",
        "numberOfKnots": "118",
        "numberOfStakeHouses": "12"
      }
    ]
  }
}