[Shaun]

You can name either parody/comedy accounts, or real people, or both.

Off the top of my head:
- Neville Southall (former Everton/Wales/Torquay goalkeeper) - has a remarkably tolerant and open-minded stance on a variety of issues and brings a lot of attention to the likes of mental health charities, transgender issues, human rights and sex workers. Just a really refreshing point of view from an ex-footballer (as the majority on Twitter are just wannabe pundits with a penchant for engaging with abusive fans)
- Paul Sinha (Chaser from...er...the Chase) - a lot funnier than he appears on the show
- Katherine Ryan (comedienne) - icon
- Omid Djalili (comedian) - also an icon
- Perfume Genius (musician) - aside from the occasional teaser of amazing music, pretty funny
- Rob Delaney (comedian/actor/writer) - I think I'm right in saying he pretty much became a big name because of Twitter?

Other (non-"person" accounts)
- Wint - the greatest of all time incomparable. Worth following the Wint spin-off that takes his tweets and subtitles them with British politicians too: https://twitter.com/parliawint