Chokers go with exposed decolletage and lower-cut tops, while high hemlines like turtlenecks look best paired with longer chain necklaces. That is just the science of achieving balance in fashion.
Now, as fashion rules go, nothing is set in stone. If you find that a massive pendant with lots of detailing looks great paired with a leopard-printed halter neck top - then you do you, boo.
Yet if you are in dire need of some balance guidance, here are some lovely tips:
Jewellery seen on models:
Chunky necklaces, Pichulik.
Long brass pendant, Waif.
Leather choker, Matter of Fakt.
Insideoutstyleblog has a whole list of recommendations if you wish to know even more.