Note: This is a list of Nation's that existed for a significant duration following the First World War. This does not necessarily mean these nations exist in this form in Modern Europe.
- Republic of Estonia
- Republic of Latvia
- Republic of Lithuania
- Kingdom of Finland
- 2nd Polish Republic
- Free City of Danzig
- Russian Soviet Federative Socialist Republic
- Transcaucasian Socialist Federative Soviet Republic
- Ukrainian Soviet Socialist Republic
- Byelorussian Soviet Socialist Republic
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