What size of multiplexers are needed?

Could you please elaborate on the context and specific requirements for the multiplexers you're inquiring about? Are you working on a project that necessitates a particular number of inputs and outputs? Are there any constraints in terms of power consumption, speed, or cost? Understanding these details will help me provide a more accurate and relevant response to your question. Additionally, do you have a preference for a specific type of multiplexer, such as digital or analog?