Hi D,
Monzo have been teasing and suggesting the implementation of Cash ISAs and there was a sign-up if you’re interested thread somewhere. EDIT: Join the waitlist for ISAs with Monzo
This looks like they are getting ready to implement so I think we shall hear more soon! We don’t really have a lot of info on these, no interest rate % or whether they will be flexible or not - but as it is in the next batch of updates hopefully it isn’t much longer now!