Blindsight+Echopraxia by Peter Watts
Three body problem by Cixin Liu
EDIT: Also tons of free ebooks at baen.com. Typically 1-2 firsts of a series.
Monster Hunter series by Larry Correia also come to mind.
E2:
Into the Looking Glass by John Ringo
Boundary trilogy by Eric Flint/Ryk E Spoor
other series by Flint and also David Weber (and did you read all of the Honorverse?
)