Any stream cipher?
If you use the same symmetric key and nonce, the output bit stream should be the same every time.
This is how OpenBSD's arc4random(3) started out: using the output of RC4 and stirring the entropy pool regularly to ensure forward security. (They've since switched to ChaCha20.)
* https://man.openbsd.org/arc4random.3
Remove the stirring and you've got deterministic output. Security comes from the entropy of the initial conditions.