By surprises i mean affordable hitter who is producing a lot more that what he was supposed to. Nobody would be surprised if Trout, Lindor, Ramirez, Arenado are hitting gods...
Infielders : In my case, my (way too early) batting MVP is Corey Seager. Don't know why but his hitting is so quick and pure, this guy is a double machine. Stats are not so flashy but the results are pretty good, he's hitting >500 in my first 10 RS games.
I'm also loving Eugenio Suarez, same as for Seager, i love the swing and reactivity. But a little more of contact should has been usefull.
Outfielders : Ronald Acuna, we can debate if it's a surprise or not but the guy is not so expensive knowing he can do everything
Tommy Pham, a kind of cheap Ronald. He's a must have for low budget managers. Supposed to have 50 in vision but looks like 30-40 in game. And you can feel that he misses the famous "pressure cooker".
Carlos Carrasco, if you can handle his slider, you'll be unhittable.
Robert Osuna. That slurve is my best pitch of the game so for, combined with a hard fastball.
Blake Treinen. One word : nasty.
I would be curious to know your underrated/surprise players.
Cardinals collection Albert Pujols. The guy is an absolute animal with the bat.
(Slightly expensive i know, but regardless still amazing for me)