It's a bit hard to know who's available from the top 3 WSL sides. Although tbh almost all their players have a quality equivalent or better to whats currently here. It's hard to know which players are happy at Chelsea\City in particular if they don't play that often. If I was Beth England in particular I'd want to be playing more in seasons to come to really cement my NT place as she's not really young. Leah Williamson's contract expires at Arsenal but I really expect her to stay there, she's a lifer there I think.
Erin Cuthbert is at Chelsea but I agree she's a quality player.
Here's a list of a few top level international players who's contracts are supposed to expire this summer. Of course they may re-sign with their club, some may look to go back home etc and in info may be out of date now. But it gives us a few player names to keep an eye on. Almost all these teams will be in UWCL next season, so that may also impact on any signings and they also will be courted by other clubs. But they're worth a look.
PSG - Paredes, Endler, Nadim, Bruun
Lyon - Kumagai, Karchaoui
Bordeux - Khadija Shaw
Barcelona - Kheira Hamraoui, Sandra Paños
A. Madrid - Toni Duggan - I don't really rate Duggan tbh, I think she'll probably go to Everton. Also I don't see how they make the UWCL this season so surely alot of their other players will be on the way out as well.
Levante - Think several of their team expire inclusing Esther.
R.Madrid - Jakobsson and Asllani
Bayern - Amanda Ilestedt, Simone Laudehr, Carina Schlüter
Wolfsburg - Frido Rolfo, Ingrid Engen
I'm not sure about the Italian teams or the Scandinavian ones.
In an ideal world you'd want Endler as she's probably the best GK in the world. Engen is also a really good young Mid. Esther has scored loads this season, so has Shaw, both are CF. Paredes is a really good CB. But I don't think any really have been linked, so this is more 'hope they're shopping at this level'. Real I think will be going for a lot of people this summer, so I wouldn't be surprised for a few, especially the Levante players to end up there.