They cancelled a sitting President. If that doesn't scare the hell out of you then I don't know what will.
I can list quite a few, Carl Benjamin, Alex Jones, they've had mass banning of pro-life conservatives, Blue Check Mark watch was banned for pointing out the hypocrisy in Twitters bans. There's whole lists of people, just search on DuckDuckGo as Google censors their results quite heavily.
The fact that the Taliban and many fundamentalist Islamic groups are free to post on Twitter but not Trump says a lot.
I don't believe any US President should be banned from social media and it's a clear sign social media needs broken up and regulated. The Democrats won't do it as they are a part of the Silicon Valley cartel.
Twitter operates under the protections of Section 230 as a platform but behaves as a publisher, it's time they were either forced to behave as a fair platform or held liable like a publisher. Personally I think they should no longer be afforded Section 230 protections.