The only way I know of to get testnet coins is through faucets such as the following.
I found these faucets with a search. They seem to be actively maintained but only give 0.01 tBTC at most. Sometimes they are down or not working for me.
I would like to get at least 1 tBTC to test an application which is expecting more around 0.8 tBTC. How can I get more tBTC? I would be OK with paying for some tBTC. 1 tBTC would take a long time to collect using faucets, and I feel I am abusing their service.