The Financial Times, his former editor at the Telegraph, obviously the Guardian
I would note that all three of these are extremely anti-Brexit. Lots of people believe (rightly or wrongly) that Leave wouldn't have won without the support of Johnson and blame him personally for Brexit, which they see as an abomination. They aren't going to be even handed in their judgement of him: really, I'd say anything they write about him is going to be a smear.