Aw man, that is horrible ! 
You seem rather calm despite the disaster.
Here's hoping you can salvage most of your stuff (and with that I don't just mean the gaming stuff)
I'm calm because it's the third time in 10 years that this happens. But I was confident enough to put most of my models there because we installed a powerful water pump - it shouldn't have flooded. But alas, Mother Nature gave me and my parents a hard lesson. In 5 minutes it rained enough to overwhelm the pump. So, I lost most of my stuff due to my own fault, I can't do nothing else but be calm about it.
I'm cleaning the scale models in warm water and soap - they are full of mud - but lost all the boxes, decals and instructions. Some of the little pieces broke from their sprues and were damaged. Guess I now have a big pile of sprues for scratchbuilding stuff

Most of my GW paints - the old ones - survived pretty intact even after spending all those hours under water, same for Vallejo ones. But lost most of their labels,

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My compressor is an industrial one - without oil - so it's closed I hope it survived the water. I'll let it dry for another week before trying to start it up.
Assorted terrain got all broke, same as the model from Mainly28s I mentioned above - the pieces were too light and floated in their cabinet, bumping against everything. Lots of books were also destroyed, same for clothes (old ones and some that was left to dry). The main problem was that water that came from the street was loaded with sand and it turned into a smelly mud that enters everything.
The only thing that didn't get completely destroyed was a Warlord Hetzer that I was painting for my SOTR project - found everything (the figures were still on a bag, they floated; the hatches and guns didn't broke) except for one track. Now I have a semi destroyed Hetzer,

.
But as my brother jokingly says... I will rebuild. Yesterday I bought those 2 models, some paints and decals.