The Dropbox API /2/files/list_folder[/continue] endpoints do not offer an ordering option, but I'll pass this along as a feature request. I can't promise if or when that might be implemented though.
The entries returned by /2/files/list_folder[/continue] are returned in the order needed to retrieve an accurate representation of the state of the Dropbox account, so make sure you process them in the order received, per the /2/files/list_folder documentation. Once you retrieve all of the returned entries, you can sort them as desired client-side.
what if a list of 30k file and i just want to get the latest 3 files starting with "z" letter your suggest is: get the full list to get 3 files!!! by order i can do orderby: name sort: des limit: 3 = done
That's correct. Note however that you don't need to re-list everything each time though. Once you retrieve the full listing, you can continue to store and re-use the latest cursor you receive by calling /2/files/list_folder/continue, which will return only what's changed since you received that cursor. Follow the instructions in the /2/files/list_folder documentation to process those entries into the existing state.