Is it ok to store the plaintext hash of encrypted data Is it ok to create and store the hash (unkeyed hash function) of a plaintext before encryption or does it lead to vulnerabilities?
If it is ok are there requirements for the used hash function and encryption algorithm?

Important to mention is that the hash should not be used for integrity checks or something like that.
This will be less secure than storing only the encrypted data or storing also the hash of the encrypted data.

In your scenario, you give more options to an attacker, because it is possible to attack both the cryptosystem and the hash. For instance, think of an attacker that found a preimage attack to the hash...

Moreover, since the hash is deterministic, it allows some kinds of inference attacks, because if two stored hashs $h_1$ and $h_2$ are equal, then, they are probably hashs of the same message. This is the reason we use probabilistic encryption schemes.