Yes, in this section NODE API.
There is a method but the API key is needed:
GET /debug/minerInfo which shows all miners who has enough generating balance to be able to generate block.
api port is 6869 by default, make sure you have enabled it in your config.
There are 2 ways to sign transactions:
Use a node. But that node should know the private key of your address. In other words, it should be your node, because you should never send your private key to anybody else.
Use libraries for different languages (python, c#, js, java). Libraries can sign transaction with provided private key and send to the network already signed tx.