That is a big question. If I go to a JD dealer & ask what parts are available for a JD4010 & what are the prices. He will not give me a list of every part that JD has, he will ask me what I need. If he doesn't have the part from JD , there are aftermarket & used sources.
I deal in parts for Japanese & US tractors. Some parts I can source from US suppliers , some parts I can source from Japanese suppliers , & some parts are no longer available new , but I have to source used from salvage tractors including my own parts tractors. I do not try sourcing parts & pricing to see if they are availabloe until someone asks for them. I hope this answers your question.
I see you have a TS1610 or TS1910. They are very similiar to a TS2205. These are tractors built in the 70's. there are a few new parts from US sources. Some parts are no longer available even in Japan. I do have 2 TS1610 parts tractors , so I do have used parts availoalbe.