1st sing.: (yo) soy
2nd sing., informal: (tú) eres
3rd sing./2nd sing. formal: (él/ella/usted) es
1st pl.: (nosotros) somos
2nd pl. informal: (vosotros) sois
3rd pl./2nd pl. formal: (ellos/ellas/ustedes) son
I don't see anything missing.
Edit: unless that was a weird joke.