Off the top of my head and I am sure there are other things that could be added to this list. Most of these things that we see more often than in other breeds.
Dentals usually needed yearly - I cannot tell you how many come to me never having had one
Main reason: money .. people should be told when they purchase/adopt a yorkie about the need for this and the cost
luxating patellas
cruciate ligament tears
pancreatitis
collapsing trachea
IBD
LCP
HGE
allergies
lymphangectasia
GME
PDA
PRA
They also are not pups that children should be carrying around or rough housing with....the accidents I have seen from them being dropped is very troubling.
My vet one day was joking with me about how did I pick this breed?