This was my first terminal emulator when I got started with Linux (I skipped GNOME's one because it was completely uncustomizable). It's got many useful features and I'd compare it to Windows Terminal, but the 3 second startup times (with a good computer) were too much. After many other terminals I've now settled on Ghostty which provides the customization options I need and starts instantly. The most useful feature of Tabby which I can't find elsewhere is connecting to remote servers with file upload/download support and serial consoles (useful for people working with embedded systems).

>gnome's terminal emulator is uncustomizable

Right-click the terminal area and select "Settings". Then go to the "General" tab where there should be a setting for the color scheme.