Turbotax kept 3 years back- therefore only 2017, 2018, and 2019 would show up.
You can go to your CRA "Online Account" if you did not create one- you can go and register here.
You will be able to find the returns you have filed there.
@TurboTaxBrenda1 thanks for commenting -> on the myCRA site, I can not access actual Tax Files, which show the figures submitted (which is what I require). I see a high level amount of info, and a notice of assessment. But not the details I require. The laptop I had saved my T1 general on saw the last of its days. I typically have things backed up, but for whatever reason this was the one thing I failed to save to my thumb drive. Do you have any other advice on how to best track down a 2016 T1 general? (note: I am living abroad, and can't just pop over to Canada).
Unfortunately, if you used TurboTax Online and you never saved (backed up) a pdf of your 2016 tax return, there is nothing on my end that I can do to help you retrieve it as it is no longer on your TurboTax Online account.