Netflix and The CW have had an almost magical relationship. Since 2011, the two companies have had a deal that made The CW's scripted shows available on streaming at almost unbelievable speeds, allowing fans to catch up, binge, and re-watch almost immediately. Although their deal doesn't always include series acquired from other providers, the best CW shows on Netflix even included the 1998 Charmed series and Gilmore Girls - two shows from The WB, The CW's precursor.
The most recent agreement meant Netflix streamed new CW seasons a mere eight days after the season finale aired. The deal between the two companies ended in the spring of 2019, meaning there's no guarantee new CW shows will be available on Netflix. Luckily, it does seem like the Netflix library of CW series will remain available (for the US and UK anyway), so at least CW favorites like Riverdale, Arrow, and Supernatural are safe.
Vote up the CW shows you're glad are on Netflix and vote down the shows you'd be okay with if they disappeared off the streaming service.