Ok after some time I managed to collect most of your requested countries. Be aware that many of those you proposed aren't possible to find in any FPS game. That's why I had to drop them sadly. Anyway there you go:

Popular in games (will take more time and effort to collect everything)
- USA
- Germany
- Great Britain (British accent)
- Russia
- China
- France
- Italy
- Japan

Less popular in games (will take less time and effort)
- Finland
- Belgium
- The Netherlands
- Ukraine
- Turkey
- Vietnam
- Spain
- Portugal/Brazil
- Arabic
- Latvia

Very unpopular in games (they only have few voicelines in only 1-2 games)
- Greece
- Sweden
- Norway
- Denmark
- Albania
- Austria
- Lithuania
- Czechia
- Mexico
- Hindi

The ones I had to drop: Afrikaan language, Malaysia, Rhodesia, Wales, Mongolia, Philippines