Great Question!
PORTUGUESE GUITAR
@susanc is right, fado is a good example where they use a lot of Portuguese guitar. Often, that’s the only instrument they use.
Carlos Parede is by far our most-known Portuguese guitar player. His father, Artur Paredes was also very important as a Portuguese guitar player.
Besides those two, we also had other great players such as José Nunes, Fontes Rocha, Jaime Santos and Raul Nery.
PORTUGUESE MUSIC IN GENERAL
That depends on what genre you are interested in.
We have a lot of great rappers like Sam the Kid, Boss AC, Sp & Wilson, Valete and Da Weasel.
If you are interested in rock then you have to check out Xutos & Pontapés. They have been active for over 30 years. They’re our “Rolling Stones”.
As for Pop/Rock music I’d suggest Rui Veloso, Sérgio Godinho or Pedro Abrunhosa, both of them very popular.
Another very popular genre nowadays is called Kuduro. It has African origins. The most popular representative for this genre is definitely Buraka Som Sistema.
If you’re interested in some other genres, by all means let me know!