Australia
Edit: assume via Singapore also doesn’t work?
De-facto they are preventing citizens from entering but de-jure they are still allowed. But I mean it's China, is anyone surprised here?
"Japan suspends new reservations on all incoming flights" https://apnews.com/article/coronavirus-pandemic-health-japan...
This was a short lived measure but did have the effect of preventing some citizens from returning. It could be argued that they could travel by boat, but I believe most ocean travel was also restricted at the time.
An edge use case - but one I've enjoyed - was visiting Israel and then traveling on to other countries in the region. An Israel entry stamp can cause issues entering other Middle Eastern states but, in my case, I used a different passport when traveling to other ME countries.