1. East Slavic Group:
- Russians
- Ukrainians
- Belarusians
2. West Slavic Group:
- Poles
- Czechs
- Slovaks
- Kashubians (Poland)
- Sorbs (Germany)
3. South Slavic Group:
- Serbs
- Croats
- Bosniaks
- Montenegrins
- Macedonians
- Bulgarians
- Slovenes
It's important to note that these divisions are based on geographical, cultural, and linguistic similarities, and individual countries and ethnic groups may have further subgroups or variations within these major categories.