Most properties are let out either Partially Furnished or Fully Furnished. As the name suggests, it is partial when only some pieces of furniture come with the rental, viz Aircon (at least in the bedrooms), Lights, Curtains, Fridge & Washing Machine. There will be wardrobes at least in the masterbedroom, and kitchen cabinets.
A Fully Furnished deal would also have bedroom sets, sofa & dining sets, display or cabinet stands/shelves for TV, HiFi, etc. Whether TV & HiFi sets come with the lease depends on the level of the rent, how desperate the landlord is, condition of the place, etc. One usually also gets utensils for cooking & dining eg pots, kettle, cooker, plates, cups forks & spoons.
Some tenants may want to negotiate from a partially furnished package to a fully furnished deal so there is no need to worry about other furniture items. The differential in terms of monthly rent is usually between S$100 to $450 a month, depending on a) size of the property (eg more bedrooms will require more furniture), b) length of the lease & rental level, c) if items are to be brand new or used, and d) if there are a lot of (new) appliances to be included - some tenants want (2 sets) TV, HiFi, New Fridge, Washing Machine, Dryer, Dish Washer, new curtains, new paint in a colour of their choice, etc.