A collection of links to useful things I've used/built over time for Bitcoin development.
https://www.bitpost.app/tx/01c5a66cd482cca4a7df4652376be33bdb10bf89a40bbb043d79f145397b7f33
https://jsfiddle.net/atoyen4c/
https://iancoleman.io/bip39/#english
https://iancoleman.io/bitcoin-key-compression/
https://gobittest.appspot.com/PrivateKey
https://jsfiddle.net/wfotksg6/
https://jsfiddle.net/rzmwusgo/1/
https://jsfiddle.net/5ebtzcqf/3/