Meanwhile the search for right faucet is on, you can always start mining on the testnet. I received around 15 test-Eths in about 8 hours - was enough to get started.
In your Ethereum wallet, ensure you are on testnet (Develop -> Network should be testnet) Start mining by Develop -> Network -> Start mining.
In console, geth --testnet --mine is the way to do
You could instead use MyCrypto's faucet. It supports Rinkeby, Ropsten, Kovan, and Goerli testnets. Just switch your Metamask to the intended testnet and then visit the following URL to receive your test ETH:
https://app.mycrypto.com/faucet
Best Answer
There are two/three ways to get ether on your own private testnet:
Check this: https://github.com/ethereum/go-ethereum/wiki/Command-Line-Options
And this: https://souptacular.gitbooks.io/ethereum-tutorials-and-tips-by-hudson/content/private-chain.html