Most counties which formed by separating from an empire.

I mean, I guess you'd need to narrow the definition a bit.

I was thinking of a lot of former colonialised nations, but lots of those also have history of conquest before they became colonised.

Then Finland? Well, by our actions, pretty much. But O can't say that it was because people didn't want to.

https://en.m.wikipedia.org/wiki/Greater_Finland

Perhaps "proto-imperialist" would be better suited to describe that. Well, irredentist, officially. (Rather rare, didn't know that word.)