Hello, is there a way to blacklist or hide everything that I've downvoted? I've tried both voteddown:anything and with my username, but nothing seems to work.

Blacklisting downvoted posts can't work because blacklists are handled on the clientside and vote information isn't supplied to the client for performance reasons (topic #34507)

You can, however, append every search with -voteddown:me to filter it from the results.

faucet said:
Blacklisting downvoted posts can't work because blacklists are handled on the clientside and vote information isn't supplied to the client for performance reasons (topic #34507)

You can, however, append every search with -voteddown:me to filter it from the results.

As an alternative solution, you can use filters like uBlock Origin, tailored to the post IDs. This has the performance issue still (at least on client side, server doesn't care), but probably no where near as bad.