Pedopenna.
This was a small, carnivorous paravian (and related to maniraptors such as Velociraptor and Therizinosaurus) that seems to have posessed wings on all four of its limbs. Its feathers weren’t as advanced as those of the similar Archaeopteryx, being more flexible and not as strongly adapted for flight. There is some debate over whether Pedopenna was related more closely to the deinonychosaurs, or modern birds.

It also possessed a specialised killing claw, like its deinonychosaur relatives, though the claws that Pedopenna had were far more primitive. And unlike the deinonychosaurs (and most modern birds) its flight feathers were all symmetrical (the restoration doesn’t show this), which means it would probably have been early in the evolution towards effective powered flight, or in the process of “devolving” these structures to the function of display.

(The fossil is of a Microraptor, but it is almost identical in appearance to Pedopenna, as far as observations have supposed. Only the hind leg of Pedopenna is physically known.)