A few sites worth keeping an eye on in the coming weeks of the UK general election campaign:
Democratic Dashboard – If you are a UK resident this is a good place to find tailored information on the elections in your area.
UK General Election 2019 poll tracker – from the Guardian.
UK Polling Report – blog by Anthony Wells of YouGov.
Electoral Calculus – analysis site by Martin Baxter with a lot of valuable data, though its seat calculator is controversial. Best treated as 'a bit of fun' in the spirit of John Snow.
Region by Region Guide – a short regional overview (excluding Northern Ireland) from Chaminda Jayanetti at Politics.co.uk
Northern Ireland Elections – excellent reference site by Nicholas Whyte.