Online markets:

• Paid.co (⚡)
• Bitify

And then this (older) post on r/Bitcoin has a bunch more methods:

Ready to cash out some $BTC? Spend your bitcoin instead
https://reddit.com/r/Bitcoin/comments/cbqi1o

You might also find this from browsing my Tweets:

https://twitter.com/ClubAlpaca/with_replies
https://nitter.it/ClubAlpaca/with_replies

List:
https://twitter.com/i/lists/70383829
https://nitter.it/i/lists/70383829

List Members:
https://twitter.com/i/lists/70383829/members
https://nitter.it/i/lists/70383829/members