Thanks, just hope when people ask about the best chain Hive keeps showing up on the list near the top!  I have a few search results likely useless yet here are a couple few links

step by step for beginners
https://www.splintertalk.io/@elebrum/splinterlands-data-exploring-for-beginners

github read me looks full of info
https://github.com/kiokizz/Splinterlands-API/blob/master/README.md

general sl api
https://www.splintertalk.io/@solaito/unofficial-splinterlands-api-documentation

maybe this one for market
https://peakd.com/hive-13323/@ecko-fresh/c-tutorial-how-to-use-splinterlands-market-api

here for card sets
https://peakd.com/hive-13323/@holoz0r/tutorial-using-the-splinterlands-api-and-knime-to-determine-what-cards-you-require-to-complete-your-untamed-collection

api bot learning
https://hive.blog/hive-13323/@wohefengyiyang/re-tobyshou-r8slr2

buying cards
https://hive.blog/splinterlands/@tcpolymath/step-by-step-api-calls-for-buying-a-splinterlands-card

this one charges $10
https://splinterlands.app/private-api/

somethin extra
https://www.reddit.com/r/Splinterlands/comments/qtyvee/i_created_a_website_to_display_splinterlands/