If you want an underrated but fecking good striker, take a look at Marquinhos from Palmeiras - plays AM RLC/F C. Depending on how the dice have fallen when you started the game, he might not be able to become truly world class, but hes young and definitely worth a punt.
i signed him for £8m, and a few seasons later (in the 2014/15 season), here he is:
http://img32.imageshack.us/i/marquinhosg.jpg/
as for midfielders, my recommendations are Ignacio Camacho (starts at Madrid, hes solid, if not world class, can probably get him pretty cheap).
Or you can try Kuzmanovic, random Serbian midfielder. Again, not world class but one notch down.
Other, better well known names include Veloso, Zapater and Moutinho. Rodwell and Fellaini can be competent too.