There is also gambling, but of course there is an element of risk.
Honestly I think the best way to obtain Bitcoins is just to get a day job and covert some of your fiat to Bitcoin. Much more efficient, and less risky, than trading/gambling.
I don't recommend this, but you could also try to scam someone
i like this recommendation except the last one
and for TS, so many thread about how to earn, you should roaming around to gather information then post a new thread.
btw this thread became a new source of sharing new idea of other bitcoiners
The first two are not great though. So many coins are pump/dump altcoins are not near as easy to predict. And if you had all holdings in altcoins look at what you would have missed out on BTC value.
Gambling is a loss over time. No matter how good you are, over the long term you lose. So you are not investing smart with gambling.
Buying is the quickest way to get BTC coins, that is for sure.