As a pure Ruck, Darcy is the best option of those younger latter ones you mention...Longer is finished due to concussions.
Grundy wont come here and would cost too much.
I think Goldstein will stay at North but is worth a look (FA). Id maybe take Ryder or Jacobs but only for a year and i think they would want longer deals to move interstate.
Id still push for Darcy if Kelly likes Freo.
Outside of that to cheap options I like Smith who is back in the queue at Brisbane but has talent or Hayes or Frampton at Port.