I remember two experimental cmavo proposed on this list:
xa'o (ZAhO) indicates the time when an event should be continuing after it has
actually stopped (opposite of za'o)
and
xi'i (XIhI) terminator for xi; used in mekso to disambiguate e.g. one variable
with two subscripts and a variable with a subscript that itself has a subscript
Were there any others?
phma