The big one in the middle is a 100 mon from Japan, mid-1800s. An example in somewhat worse condition is in
this thread.
Top left is a 5 sen from Japan, Meiji Year 4 (1871), a scarce one-year-type.
NGC page.
Bottom left is Chinese, a small machine-struck cash of Kwangtung province, early 1900s.
Top right is A Chinese cast cash, in the name of the Qian Long emperor (1735-1796), Revenue mint. I might be able to narrow that date range a bit when I check my references at home.
Bottom right is also a cast Chinese cash, this time from the reign of the Dao Guang emperor (1820-1850). I can't read the mintmark on the back.
Your "very worn coin" is a mediaeval Byzantine "anonymous follis" depicting Christ on one side and the cross on the other. Class I (that's class nine, not class one), attributed to the reign of emperor Nicephorus III (1078-1081). In better condition it would have looked more like
this one on Wildwinds.
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