You have plenty GNU/Linux compatible OOTB laptop manufacturers like:
Also check this for buying preinstalled libreboot laptops (some of the upper ones already do) minifree.org and here how to do yourself if you feel confident libreboot.org
Also you can consider buying a Dell laptop or Lenovo Thinkpad
I strongly recommend buying a laptop with AMD graphics, either integrated or external, for getting the best compatible machine for GNU/Linux, and avoid Nvidia, and Intel too if possible