I don't think they do anything (Eurooptic), but there are always a ton of returned or marked down items at EO. SWFA always does Black Friday as do various other manufacturers (Tract Toric). Just keep your eyes open, there will be posts about various promotions. At this point, if you have a favorite manufacturer and you aren't on their mailing list (where you will get promo email) , you have only yourself to blame.
Also note that SWFAs used stock:https://www.samplelist.com/ will have additional discounts on Black Friday.
Also note that SWFAs used stock:https://www.samplelist.com/ will have additional discounts on Black Friday.