There are many project management certifications, the top two are:
PMP: Project Management Professional (offered by PMI)
PRINCE2: PRojects In Controlled Environments 2 (offered by the APMG)
Other project management certifications are (in order of importance):
- CAPM: Certified Associate in Project Management (PMI). The CAPM is mainly sought by Assistant Project Managers.
- PgMP: Program Management Professional (PMI). The PgMP is strictly for experienced program managers. It is the most exclusive project/program management certification.
- APMP: Project management certification offered by the APMP (Association of Project Management Professionals)
- IPMA Level a, b, c, and d: Level a is a certification for project directors, level b is a certification for senior project managers, level c is a certification for project managers, and level d is a certification for project manager associates (all are offered by the IPMA - The International Project Management Association - A Swiss non-profit organization aimed at promoting project management).
There are also, of course, the PMI-SP (for project schedulers), the PMI-RMP (for project risk managers), and the PMI-ACP (for agile project managers)