I login to marketplace.magento.com and when I try to download my old purchased (free ones or not) of extensions, all of them goes to 404.
I search some extensions for Magento 1.9 and in marketplace I only find the filter of version for Magento 2 and above.
Why marketplace limit the extensions to Magento 2. And if they are exist in other places I want to know.
Magento 1 reached EOL (end of life) in June 2020 and Adobe decided that it would remove all M1 extensions from Marketplace and Magento Repo shortly after in an effort to encourage sites to migrate to M2. You can see some details here https://community.magento.com/t5/Magento-DevBlog/How-Extension-Developers-Can-Prepare-for-M1-End-of-Life/ba-p/446216
If you know the extension developer, I'd recommend contacting them directly for support - they may still offer the extension on their website or their Github.
