Thanks to sv3n information I managed getting all available Free extensions in Magento Connect.
There are 3910 paths to extensions in packages.xml
file. About 550 extensions are already dead. I checked most of them in Magento Connect using Direct Download extension for Chrome and they won't download. Package information for these 3910 extension still exists and can be download separately. It will help you finding the authors on Internet (GitHub mainly).
The size of all 2600 extensions available in total is about 600 MB.
Over the years the number of free extensions dramatically decreased from 6500 to 2600 as we have today. You still can find extension page for all 3910.
Seeing those figures it is clear to me Magento Inc. intention is vanishing Magento 1 in the next year. The decision related to Magento Connect is a correct one, as now Magento Connect provide only information about potential extensions. It is like cutting trees and you still expect fresh air.
Marketplace is far away from what we saw years ago in Magento Connect. There are 200 free extensions but they cover only a little part of the issues. For Magento 1 this is a dead end (my personal opinion). A list of Magento 1 developers was a better option. Sad many developers will not update their information in Marketplace.
For those who want continuing with Magento 1 starting with September the 15th they will have to spend more time to get what they need. They can ask someone who knows what to do and has good knowledge or using Google for digging thousands of pages. GitHub is a good resource now.
I could switch to Magento 2 but I don't like the backend interface and Magento 2 is lazy on my dedicated server comparing with Magento 1. Many things are good in the new version but speed is a big issue to me.
Starting with September the 15th we close an important chapter in Magento 1. This version is condemned to extinction. If Magento reads this comment please improve speed in the new versions and organize the backend, it is the worst backend comparing with WooCommerce, Prestashop, Open Cart, CS-Cart, X-Cart.