#1: agree it's a button or some similar artifact.
#2: appears to be a Byzantine "anonymous follis" class B, attributed tot he reign of Romanus III. That bright green coloration is of concern as it's likely to be bronze disease.
#3: Islamic. Seljuq or Mamluk by the looks of it.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis