Any ravaged by the empire, war-torn planets that Luke/Han/Leia/rebels etc could visit to clear up imperial remnants, close after the end of ROTJ? Any universe - I'm no good at plucking names from the air.
A few that could work:
Derilyn, a planet in sector M-19 where the capital city was destroyed and most of the population killed, which was liberated by the New Republic
Bespin was only truly liberated just after the Battle of Endor. While not canon, Luke, Leia and/or Han could plausibly have gone to help fight at some point.
Luke was sent to aid Bakura very soon after the Battle of Endor, not strictly to fight against the Imperial remnants but to defend them from the Ssi-ruuk. However, it did result in the Imperial forces being overthrown and New Republic control over the planet’s precious metals.
Dantooine was reclaimed by the Alliance soon after Endor.
At some point after 4 ABY, Felucia was brought under New Republic control, but it is not known when or by who.
Thyferra, the only major source of bacta in the galaxy, was liberated in 5 ABY, less than a year after the Battle of Endor (though the New Republic never occupied the planet). Luke probably played a role, as he had fought at Thyferra before.
Kashyyyk, which was under strict Imperial occupation, was freed in 4 ABY before being reclaimed by the Empire and again freed in 5 ABY. The second liberation was aided by Han and Rogue Squadron, so Luke and/or Leia could also have been there.
I’m certain there are countless others that could work, as most planets were under Imperial control up until 4-5 ABY and were freed by the New Republic. Those that were not freed soon after Endor were generally those protected by Grand Admiral Thrawn, such as Corellia, or the Deep Core worlds like Coruscant.
I hope one of these works for you. Good luck!