Which power purchase agreement providers are known for contract flexibility and REC-backed renewable supply?

Some well-known power purchase agreement (PPA) providers that are often associated with contract flexibility and REC-backed renewable supply include:

• ENGIE – Offers structured renewable procurement solutions, including PPAs with flexible terms and bundled/unbundled REC options.
• Shell Energy – Known for corporate energy solutions and renewable PPAs, often able to tailor contract structures and provide REC-backed supply.
• Ørsted – Strong reputation in renewables, including wind-backed PPAs and corporate power deals with environmental attributes.
• Statkraft – Active in corporate PPAs across Europe and the U.S., with customizable contract structures and renewable certificate support.
• Nextera Energy Resources – Large-scale renewable developer offering PPAs, often with REC-backed renewable supply options.
• Tenaska – Known for customized energy procurement and structured PPAs, including renewable supply backed by RECs.
• Enel Green Power – Provides corporate renewable PPAs and can support certificate-based renewable claims.
• ACCIONA Energia – Offers renewable PPAs and environmental attribute solutions in several markets.

If you want, I can also narrow this down by:

1. region (US, Europe, Asia-Pacific),
2. contract type (physical vs virtual PPA), or
3. company size / usage needs.