Originally Posted by rccardr

If you want an old-school blocky design aesthetic, then anything 6-7-8 speed Deore from 550 series on up will do the trick.
Some are shinier than others. Low mileage and NOS examples abound, and yes, they will happily shift across a 10 speed freehub.
Side note: I know you are friction shifting, but said RD will also index with anything Shimano from 6-7-8-9-10 speed groups except the infamous DA 740X.