Bitmixer - Voluntary Shutdown - largest bitcoin mixer.
Bestmixer - German BKA, US, Europol
Blender.io
Added to the list.
OP, you will have lot of work as actual list of such websites is long. My memory is really bad and I'm a bit lazy to Google on my phone, so, I can't you help much with updating list. Now I only can remember Bitmixer.io (if I'm not wrong), one of first big Bitcoin mixers. They shutdown for voluntary reasons officially.
And damn, BTC-e was seized in 2017 - that's already 8 years. Time flies so fast. Still remember having account there.
No, worries we can update them bit by bit..