Another one I use quite often.
The idea of tabale topics comes of course from Toastmasters, but it fits an ELT classroom very well.
I keep them in jars at all times in the classroom and use as warm up or simple as a part of public speaking training.
I usually start with them in pairs so as not to stress out poor fellows to much. We do the table topics in front of the class usually at the end of the year.
Most of the topics that I use for more advanced students come from this source: https://www.dist8tm.org/assets/tm–365-sample-table-topics-questions.pdf