This might be the latest list of MEP candidates, although I can't see Greens in every region, or Brexit Party at all.
inews.co.uk/news/politics/european-elections-2019-candidates-mep-who-standing-eu-vote-full-list/
With several Remain parties, plus Labour who may become more Remainy closer to the date, it doesn't look good for returning many pro-EU MEPs.
The parties decided not to form an alliance and work tactically together to effectively use votes. So voters will have to be tactical. This is all we can do now, but it'd need a huge campaign to create awareness.
This article will need updating, but it suggests people vote for certain parties in each region to pool votes to full effect. Eg. in my area it says Remainers to vote Green. And in the North East for Lib Dem.
medium.com/@Metatone/a-strawman-on-ep-election-tactical-voting-for-remainers-9b17edcdbcfd
Tactical Voting
Key concepts about the UK EP elections:
Votes are counted and applied to seats using a regional list system, which means who you should vote for depends on where you are.
In Northern Ireland they use STV, but all the other regions use D’Hondt and going by previous results D’Hondt in these circumstances generally means a party needs to get a minimum of at least around 9 or 10% of the vote to get a seat (but for example in the North East last time, the threshold was 18%).
Because we hope for a decline (probably minor) in the UKIP/BrexitParty/Tory turnout and an increase (we hope a major one) in the turnout of Remainers all of the following ideas are open to discussion.
There appears to be no existing official co-operation between pro-Remain parties and at the time of writing it does not appear there is time or will to create one, so it is down to us, as voters, to make some hard choices.
As of writing the LibDems and the Greens are neck and neck in polling and this suggests that the LDs have not recovered from their losses in 2014, but equally have not fallen away further.
I think assumptions are based on the 2014 election, so things are a bit different now, but it's a start.
I don't think many Brexit party candidates are very attractive - Anne Widdecombe?? And I reckon there'll be a bigger turnout of Remainers this time. However we still need to get those young people signed up. Many young folk are more focussed on environmental issues than Brexit, so it's worth pointing out that working with the EU is the best way to pass laws to preserve the environment. It's truly a global issue which needs co-operation between nations to improve.
www.vfyf.co.uk