Unifocal PVCs all have a single morphology. Multiple different QRS morphologies are termed "multifocal PVCs" and usually originate from different locations in the ventricles. In general, there is no P wave identified before a premature QRS complex.

What rhythm has no P wave?

A junctional rhythm is characterized by QRS complexes of morphology identical to that of sinus rhythm without preceding P waves.

Does ventricular fibrillation have P waves?

In VFib, there is a rapid irregular tracing but p waves and the QRS signal are unidentifiable. In most ECG's, AFib results in a rapid irregular pulse (QRS signal), while VFib results in no pulse (no clear QRS signal) so the ECG's are quite different.