If it's just casual experiment, most likely don't need 0.5-0.7tBTC. You could just use 1 sat/vbyte as TX fee and send only send very small amount of Bitcoin on each output address. But if you insist you need lots of tBTC, you either have to
1. Explain in detail why you need lots of tBTC. Most people wouldn't give such amount due to tBTC scarcity and potential you fell for scam.
2. Use all faucet which already mentioned.
3. Mine tBTC with your own device. While difficulty on testnet is too high for CPU/GPU, you can try your luck by mining block with difficulty 1 if there's no block mined in last 20 minutes.