From HM King Gustaf VI Adolf funeral I just know some royals who attended it.
Besides the Swedish Royal Family, attended the funeral:
Denmark - HM, Queen Margrethe II (his grand-daughter), HRH Prince Hendrik and HM Queen-mother Ingrid (his daughter)
Greece - TM King Konstantinos II and Queen Anna Maria (his grand-daughter)
Norway - HM King Olav V and TRH Crown Prince Harald and Crown Princess Sonja
Sayn-Wittgenstein-Berleburg - HH Prince Richard and HRH Princess Benedikte (his grand-daughter)
Thailand - HRH Princess Maha Sirindhorn
Probably many other royals had attended this State funeral