Some standard SDLC methodologies include Waterfall, Agile, and Scrum. The Waterfall model is a linear and sequential approach, with each stage of the SDLC completed in a fixed sequence. Agile is an iterative and collaborative approach that involves breaking the project down into smaller chunks, with each iteration focused on producing working software. Scrum is a specific framework within the Agile methodology that provides a structured approach to managing the development process.