Great sibsets I know:
Logan and Liberty
Hope and Griffin
Adrienne Lisette and Keegan Paul
Avery, Finley, and Emmy (all girls)
Braxton, Caroline, and Addie.
Will, Magdalene "Maggie", and Hallie
Ezra and Jubilee (LOVE this one)
Tate and Tucker (girl and boy)
Oliver and Charlie (boy and girl)
Bad sibsets I know:
Kaden, Todd, Nathan, Winter. They just don't match at all.
Jason, Heather, Kason.
Alia and Alayna
Chloe and Cadee
Taylee and Carter
Worst: Victor and Victoria. With a father named Victor as well.
George, Grace, Eleanor (nn Ellie), Claire, Anne, and Tatum. Other than Tatum I think these names all went together really well.
Jane, Henry, Mary, and Kate
Alexander and Zoe
Robert, William, Theodore and Thomas (My dad and his brothers: Bob, Bill, Ted, and Tom, haha)
I know one sibset with the names Charlie, Caroline, Cate, and Claire. All of those were WAY too similar to actually have on two people in the same family, especially twins Cate and Claire.
Amanda and Sarita
Laura and Shelby
Andrew and Alexandra
Sisters called Kalyna and Kayla. Their brothers are Kieran and Quinn, which are okay but not in a sibset.
From a sibling group of ten (non of them belong to multiples):
I believe these two are a year or so apart, when I first met them, I thought they were twins.
The other five children names are not as match-y, but still a bit out of place.