Working with Linux is much more convenient on a laptop adapted to this operating system. Still, many laptop models have hardware issues, like not working system suspension. Below you will find a list of manufacturers selling laptops optimized for Linux.
Technology
The companies listed below often build laptops based on Clevo components. At Clevo, you can build your laptop model, choose a case, processor and other components, add a logo and sell under your brand. This option is used by some companies in the list on selected models. That's why you can find very similar-looking laptops from the companies on the list.
However, not all laptops on the list are from Clevo. Many companies put a lot of effort into designing 100% of their laptop designs to provide customers with better products.
Laptops and companies
Starlabs
Starlabs is a UK company that has been selling Linux laptops since 2016. He currently has two laptops for sale. They recently added a mini-PC based on the AMD Ryzen 7 5800U processor to the lineup.
Slimbook
The Slimbook company has been operating in Spain since 2015. From the beginning, its goal was to provide Linux laptops. Currently, it offers several laptops and desktops. It also develops its Ubuntu-based Linux distribution: Slimbook OS.
System76
A company from the USA with a large portfolio of products, not only laptops. One of their products is a mechanical keyboard. The company plans to open a distribution center in Europe. There are currently six laptops on the company's offer. The company is also known for developing the Pop!OS operating system.
Video from the company's headquarters https://www.youtube.com/watch?v=uHY_QRVJOhA
KFocus - Kubuntu Focus
Currently, the company offers two laptops: a 14-inch one and a larger one with a 15.6-inch screen. In addition to laptops, the company develops Kubuntu Focus Tools software, which has, among others, energy management tools.
Laptop with Linux
The company is based in the Netherlands. The company's offer includes mainly Clevo laptops. I have not found information that the company develops its software to improve work with their laptops.
Manjaro computer
This company sells not only laptops but also Manjaro Pinephone. The company is located in Belgium. The company currently offers several laptops.
https://www.manjarocomputer.eu/index.php/en/
Framework Laptop
Framework Laptop is a laptop designed from scratch with the possibility of replacing every part. You can even order a laptop in parts and assemble it yourself. In the laptop, you can easily change external ports (USB-C, HDMI, etc.). All ports are in the laptop as so-called. "Expansion Cards", which can be changed at any time without opening the case.
DevOne from HP
A new laptop designed to work under Linux. The laptop comes with the POPOS operating system. Unlike other laptops from major manufacturers, this laptop cannot be ordered with Windows. Unfortunately, it can only be ordered in the US at the moment. In Europe, you can order this laptop as HP Elitebook 845 G8.
I posted some reviews of this laptop in a Twitter thread
Tuxedo
A company from Germany offering several laptops. In addition to laptops, the company develops Tuxedo Control Center software for managing performance settings and power management.
https://www.tuxedocomputers.com
Dell, HP, Lenovo and Ubuntu
Visit https://ubuntu.com/certified/laptops for a list of certified laptops from major manufacturers. If you are planning to buy a laptop from one of these manufacturers, check if the laptop is on the list of certified ones and additionally search in google if there are any problems with the drivers for the given model. These laptops were designed primarily for Windows and not everything under Linux can work properly.
Summary
Currently, the choice of laptops prepared for Linux is huge. It's good, you can choose something for your needs. If I had to choose today, I would consider something from this set: HPDevOne, StarBook from Starlabs or Framework Laptop.