Just tossed up https://unread.chat
It's a chrome extension that blocks read receipts and typing indicators on messenger
The goal is to make it less stressful to check messages. I find myself not reading threads at all because of the read bubbles, and think this'll help improve my response rate.
It was a quick project, only ~40 lines of code. The security-conscious can install it from source! https://github.com/raphaelrk/messenger-lowkey