Back in the days prior to Disney, there were tons of cameos in the first 6 films, although many of them were cute nods to those that helped build Star Wars. We know about appearances from George Lucas, and Jeremy Bulloch, Ralph McQuarrie, Anthony Daniels. Also, Rian Johnson made a quick appearance in Rogue One, as a tech on the Death Star. Most of these are blink and you'll miss them moments, and were meant as both easter eggs for fans and as rewards for people associated with the franchise.
But there have been a few cameos in the franchise made by famous people not otherwise strongly linked to Star Wars. Sophia Coppola, Rose Byrne, and Daniel Craig each made brief appearances. I also only recently realized that Darth Maul was voiced by Peter "Sctanley with a C" Serafinowicz. And clearly, the casting team for Lucasfilm is doing everything possible to shoehorn the entire cast of Game of Thrones into these new films, maybe as payback for General Veers being a creepy old guy in that show.
In doing a bit of research for this story, I actually learned something. Dominic West, who played McNulty in The Wire (which rivals Breaking Bad as the greatest show in the history of television), even had a line in The Phantom Menace, which now automatically makes that film one of the greatest of all time. But this isn't really a cameo, since it was before he was famous. It's more along the lines of John Ratzenberger in The Empire Strikes Back, or Kiera Knightley in The Phantom Menace.
In any case, there were a bunch of cameos in The Last Jedi. I actually only caught one, which was Gareth Edwards in the trench on Crait. Justin Theroux played the Maz's slicer at Canto Bight, the one that Finn and Rose failed to link up with and instead settled for Benicio Del Toro. Somehow I couldn't recognize him with the mustache, but my wife sure did.
Not on this list is the rumored appearance of James Corden somewhere in the early part of the film.
Check out Variety for their TLJ list, including some that didn't make the final cut...