Tamil: 247
🇰🇭 Khmer: 74
🇳🇵 Nepali: 64
🇮🇳 Hindi: 52
🇯🇵 Japanese: 46
🇵🇰 Urdu: 36
🇦🇲 Armenian: 36
🇷🇺 Russian: 33
🇮🇷 Persian: 32
🇹🇷 Turkish: 29
🇪🇸 Spanish: 27
🇬🇧 English: 26
🇩🇪 German: 26
🇫🇷 French: 26
🇵🇹 Portuguese: 26
🇰🇷 Korean: 24
🇮🇱 Hebrew: 22
🇮🇹 Italian: 21
🇵🇬 Rotokas: 12
Note: The German alphabet consists 26 regular letters, 3 „Umlauts“ (mutated vowels: ä, ö, ü) and 1 ligation (double letter: ß - spoke as a „sharp s“).


Then why count them for Germany?
Apparently OP made a separate note for German special letters but did not include them in the count in the list, it’s also 26. They could have made the specification for French too indeed, or not have made the one for German.
In some languages they count as diacritics, while in others they are separate letters.
For example, in Finnish, å, ä, and ö are independent letters. The dots don’t do anything special, just like in i.