the skull dagger:i personally would sell it on ebay and get a few $ (or £) and forget it. there are people who like those. not too many here tho. it's fopr display on a wall, not for actual use as a tool or weapon.
the two afghani knives are frequently called 'khyber knives' in relation to their use near tyhe khyber pass area or sometimes the longer are salawar or salawar yataghans (they are not yats in the turkish sense) the 'T' spine may have a very slight recurve (S) profile in the yatty ones. they generally come in a leather covered wood scabbard and the grip is recessed into the top section of the scabbard. they may have a metal chape on the tip.
the last two are traditional filipino sword forms. (i like the one with the 'D' guard.) variations are endless, and all have different type names. they look a bit like a pinute (top) and a garab (bottom), but may be variants of another named type. they generally come in wood scabbards.
the nice bhutan knife/short sword is another traditional form found in bhutan and bordering areas of tibet, tribal boundaries there are blurred a bit
. the smaller knives are sometimes called 'dossum' and the swords 'patang' in bhutan. the bhutanese ones frequently have a dragon motif embossed on the scabbards, as does their national flag. tibetan ones can have fancy scabbards like mine, but tend to be plainer from ones i've seen, like yours. the lobed wire wound grip is diagnostic. mine is below. i include a photo of the king of bhutan in traditional dress. the patang is worn on the RIGHT side, like a legionnary gladius, and drawn with the right hand in bayonet style. the national sport is archery, so i'm assuming it's there so it doesn't get in the way of a bow. doubt the king needs worry much about that tho.