Eburonia (first thought would be related to ebony but as this plant is unlikely to grow in a northern clime a better explanation is probably needed. Some way I can etymologically relate it to German brun for brown?)
Skarmander (from sicarius, "dagger/assassin" + salamander. Doubtless some local heraldic beast.)
Manticore (Shamelessly ripped off from the Honor Harrington books which I've never actually read. But I love the idea of "Manticore" as a place name).
Tesselpot (No idea how to relate this one to any real language but I love the name. Sounds like some little corner of Olde England inhabited by an eccentric German noble family for centuries, the kind that would build nutso architectural follies around their creepy ivy-encrusted manorhouse).
Hochsump (Definitely better name for a Barony or Duchy than a kingdom but the name comes from hoch, or "high" and sump which means "a wet, sunken pit, a bog" so it's "The High Sinkhole" which is fantastic).
Eratso (definitely some kind of Mediterranean country, probably a crossroads for a bazillion different lingual groups over the millennia. Name makes me think of Erictho who was a witch in Greek/Latin literature so the land might be named for one of those powerful wizardy-types who are always getting themselves immortality or minor godhood. Maybe it's said the Goddess still sleeps in a smouldering local volcano).
Vauntlythe (I don't know where I got this sound except it kind of sounds like "Dauntless" and "Vaunted" which are cool quasi-medieval words ascribed to knights, but that ending also makes me think of lethe---you know, the pool where the water makes you amnesiac? So like a timeless country or a land out of time, like a magic castle that appears here and there maybe to hold Christmas/Spring feasts with dancing and contests and Deeds of Great Danger and Worth being declared. I really like that idea, like Castle Vauntlythe just appears sporadically around the setting and its undying king is always welcomed by the changing realms of mortalkind).
Marcelesse (Okay this is a stupid stupid pun but hear me out: few things are more medieval than bad wordplay, and also it sounds like Marcellus which is a name from Antiquity. Perhaps the quasi-legendary first founder of the country akin to Brutus of Troy for Britain? And then the local knights all just ran with it because how awesome is it to say "reke ye I am of the Countrey Marcelesse!" and ofc. the local chivalric brotherhood is The Marcelesse Order.)
Terraunce (Apparently the name "Terrance" is derived from Latin Terantius, which nobody knows the origin of. Obviously I like it as a country name because you've got that "Terra" in there. Sounds like land and sounds like terror, a lame pun Games Workshop has made meal of for decades). Plus "Thierry" is one of the more common Franco/Belgian medieval noble names so how would you like to be le Comte Thierry du Terraunce? You can just imagine that asshole being crane-lifted into the saddle in his ridiculous joust armor with like a visor in the shape of the sun and more sun-shaped crests on his shoulders like "aughn-haughn-haughn, fighte-moi, mon ami!"
More later as I think of them maybe or also maybe never