What is the fastest way of getting the last 100k block number + block hash pairs for free?

Looking for this data on ethereum mainnet specifically to use in a script

cypherpunk wannabe, engineer working on @frames /open-frames /opencast
https://stephancill.co.za create stories at https://stories.steer.fun

To me it sounds like the best approach would be to collect every incoming block continuously in order to maintain this data over time. You can then fill your queue backwards sequentially and keep the new blocks coming in.

If you try to load too much of the same data all the time, you are probably doing something wrong.