import re
text = '''
(A) Match these:
*** star* st**r
(B) Not these:
800*m *4,500
(C) And not these:
800**m **4,000
'''
print(re.findall(r'(?<!\S)(?!\*+\d)[a-zA-Z]*\*[a-zA-Z*]*', text))
aW1wb3J0IHJlCnRleHQgPSAnJycKICAgIChBKSBNYXRjaCB0aGVzZToKICAgICoqKiBzdGFyKiBzdCoqcgoKICAgIChCKSBOb3QgdGhlc2U6CiAgICA4MDAqbSAqNCw1MDAgCgogICAgKEMpIEFuZCBub3QgdGhlc2U6CiAgICA4MDAqKm0gKio0LDAwMAogICAgJycnCnByaW50KHJlLmZpbmRhbGwocicoPzwhXFMpKD8hXCorXGQpW2EtekEtWl0qXCpbYS16QS1aKl0qJywgdGV4dCkp