This is part of a series of predctions regarding Nike 2019-20 kits.
First of all, let's talk about the template. While I can't give 100% certainty, Nike will probably use a template very similar to this one for their home and away shirts next season (For instance, you can see an example here: https://www.footyheadlines.com/2018/10/nike-usa-2019-womens-world-cup-away-kit.html). I'm not so sure about the shorts and socks, though.
As for the third kits, Nike will go for a 90s approach to their designs. This will likely include polo collars and distinctive graphics, as well as using their "old" logo (with the name "NIKE" above the swoosh). Talking about Barcelona, the colours for the three kits come from leaks. According to them, the home kit will also feature a chequered pattern, while the away one will have a blaugrana sash. Lastly, I decided to use Barça's iconic 1997 kit as a reference to the graphic on the third kit.