What is, in your opinion, a necessary set of minimal restrictions on freedom of thought, speech and expression?

It seems to me a repeating pattern that once freedom of thought, speech and expression is limited for essentially any reason, it will have unintended consequences.

Once the tools are in place, they will be used, abused and inevitably end up in the hands of someone you disagree with, regardless of whether the original implementer had good intentions.

As such I'm personally very averse to restrictions. I've thought about the question a fair bit – there isn't a clear cut or obvious line to draw.

Please elaborate and motivate your answer. I'm genuinely curious about getting some fresh perspectives.