For SAFE rounds, in many cases the SAFE itself is the term sheet. For priced rounds, NVCA model documents include a term sheet
https://nvca.org/model-legal-documents/ . The more standard deal documents are, the more streamlined and lower cost the legal process will be.
References "Venture Deals: Be Smarter Than Your Lawyer and Venture Capitalist" and "The Business of Venture Capital: The Art of Raising a Fund, Structuring Investments, Portfolio Management, and Exits" provide detail on all aspects of term sheets.