Here are the correct indefinite articles for each term you provided:
-
legumbres (indefinite) - las (but "unas" also works as an indefinite article)
- Correct options: unas legumbres, las legumbres
-
autoras (indefinite) - unas
- Correct option: unas autoras
-
the nationalities - las nacionalidades (not indefinite, but definite)
- Correct option: las nacionalidades
-
some maps - unos mapas
- Correct option: unos mapas
In summary:
- unas (or las for definite)
- unas
- las
- unos