In #2, Han and Leia using a stolen AT-AT Walker to attack Darth Vader - and Vader holding his own against it!
For that matter, the fact that they only needed to do this because Luke tried to confront Vader for killing Anakin Skywalker and Obi-Wan Kenobi, only for the cocky young hero to get utterly schooled while Vader dismissively deals with him.
#6 has Luke successfully fighting Boba Fett long enough to make an escape despite having been blinded by one of Fett's flash grenades.
The opening of the the Vader Down crossover has a rebel fleet engaging Vader in his personal fighter, but Vader's sole TIE is slaughtering the rebel's ships. Realizing that a direct attack won't be enough to stop him, Luke rams his X-Wing right into Vader's ship, taking it out at the cost of his own.
Issue #36: After a scuffle with Scar Squadron ends with C-3PO in Imperial hands, the Rebels are naturally reluctant to risk going into an obvious trap to get back a protocol droid. R2-D2 however has other plans. Stealing an X-Wing, he sets it adrift in the path of the Star Destroyer. Once he gets picked up he tases the containment team, slices into the ship's computer, and begins to wreak havoc on the crew, leading squads of Stormtroopers on wild goose chases, through anti-intruder flamethrowers, out airlocks, down garbage chutes, and into firefights with each other. During all this confusion, he rescues Threepio and they make their escape. Unfortunately, onboard this ship was also Darth Vader, who, after doing what he does best, takes off after them personally. On the bright side, Artoo learned to fly from the best (whom ironically is now chasing them), and manages to avoid getting blown out of the sky long enough for Luke, Han, and Sana to show up and jump Vader from behind, throwing him off just long enough to get away.
