In Islands, you can input /command to see what commands are available. As far as I can tell, the same isn't available in Survival. Personally, I know this would help me out a lot, but if there's a way to check them all that I'm not aware of, please let me know!
As far as i know, there is no way to show all commands available. I definitely agree, that this would be a nice thing to have though. It would also be really helpful for both new players, but also for experienced players that just want to learn more.
