The only one I’ve ever seen used in real life is [name]Elena[/name]. I know two. [name]One[/name] pronounces it a-LAIN-A and one [name]ELL[/name]-enn-ah.
[name]Briony[/name] is the only name I think would be familiar to people in the UK.
In the US, I’ve come across [name]Elena[/name], [name]Ada[/name], [name]Flora[/name], [name]Arabella[/name], [name]Delilah[/name], and [name]Ramona[/name] quite a bit recently but I wouldn’t say those names are ‘popular’. [name]Arabella[/name] and [name]Ada[/name] are the two I would peg to become a bit overused in the future–particularly [name]Arabella[/name].
[name]Just[/name] to let you know (as I’m sure [name]Ottilie[/name] is aware), only the top 66 UK girls names where given to over 1000 babies last year, so if you wanted that list for the UK you’d be finding over 5700 names on your hands!