This has probably already been mentioned on /p/ - but for those who are unaware and enjoy some free filters:

The NIK Filter collection is now entirely free - Looks like Google bought them out in March:

https://www.google.com/nikcollection/

I've been using the collection for years already - and it's worth the download if just for the RAW Pre Sharpener alone.

The rest of the set is great too - good for experimenting. So yeah, party on.