The best color scheme is a hotly-debated topic. And for good reason! Lots of talented people put together some really good-looking color schemes, including:
This is, by no means, an exhaustive list. I've used each of these in the past and really enjoyed each one. However, I never really felt at-home with them.
Enter Gruvbox.
There's something so supremely, comfortably satisfying about Gruvbox. The assignment of colors to code constructs just makes sense™. Keywords in red. Functions in green. Types in yellow. Fields and variables in white. Parameters in blue. The harmony of colors and how they represent various elements in source code is perfectly balanced, so much so that anything else looks sub par. I feel like I can skim through code using these colors to find important landmarks such as function definitions effortlessly, even without really reading the code. Treesitter deserves some of this praise too for its semantic highlighting capabilities that allow the color scheme to integrate more closely with each language.
I recently tried to switch to the Melange color scheme. Melange is another warm color scheme inspired by Gruvbox. I did enjoy using it, and it does look very good. However, I just didn't feel as productive with it. It felt like I had to expend more energy and brainpower to navigate complex code without my usual colored landmarks. This only lasted about a week before I came crawling back to Gruvbox. There's nothing wrong with Melange, it's just... not Gruvbox.
Everyone is entitled to their own opinion, of course, but if your opinion is not "Gruvbox is the best color scheme", I'm sorry to say, you're wrong. Gruvbox is the greatest color scheme of all time... my beloved Gruvbox.