Mine is almost certainly almost the minimal case, except for someone running in Delaware. Federally, I file quarterly 941s (employee tax withholding), annual 940 (unemployment) and 1020 (tax return). In Delaware I final annually (stamp tax). I then file locally for Washington (excise tax) and Seattle (licensing tax).

I believe a freelancers wouldn't file employee tax forms. They frequently roll their filings into their personal taxes.

[edit: this is for a C corp]