Products I use;
Sennelier Watercolour, https://amzn.to/2LK9Im5
Canson Watercolour Paper, https://amzn.to/2OjQ6qF
Sharpie Pens, https://amzn.to/2PZuscF
En plein air does not have to be painting. Why not give drawing outdoors a try? Drawing is the foundation of all art. If your drawing is strong it will make you a better painter and a better all round artist.
Take yourself and your drawing supplies outside and give en plein air drawing a try.