Last time I looked, which admittedly was a couple of years ago most of the companies that were trying to make that work had either failed and closed down because the shipping costs were more expensive than the payout. Couple that with the need to isolate the filament types and things like carbon fiber and other abrasive filaments and it gets to be too complex to maintain unless you are running an actual print farm. The best way I’ve seen used on an individual level was melting it and pouring it into silicon molds to make things like lunchroom style trays and other “useful, but doesn’t need to look pretty” items.
At least in Germany, the company recyclingfabrik.com exists for a few years and seems to be sustainable.
They only accept PLA and PETG and you have to send your material sorted by type. Color sorting is welcomed but optional. They are able to check purity of the material to prevent contamination.
Some local filament factories also accept material for recycling, e.g. Recycling Program | FormFutura
There is also the project “precious plastics” that collect and recycle all types of plastic around the world: Map - Precious Plastic Community
I have no first hand experience with them.
Some more recycling sites I found:
Prusa also maintains a map of recycling sites:
So there definitely are options 
My poop is inconsistent.
Multi material types in the one print…Would make the worst filament on earth…Or the best? Who knows?
This exactly is near impossible unless you do a lot of sorting and don’t mix print filaments.