Yes corporate directors are allowed. A corporate entity from most other countries can be used without restriction but the corporate entity must still be on the register of companies wherever it is registered and it should be kept in good standing. Its objects must also allow it to act.
A Seychelles IBC can also be used but it cannot be used in a professional services capacity (also known as a nominee) unless authorized. If a Seychelles IBC is used as a corporate director it must act in a real capacity, actually have control, and maintain books of accounts and other records.
Only a Seychelles IBC that is wholly owned by a licenced corporate services provider can be used as a professional director to any number of other client IBCs.