Kitty is a very nice and fast terminal that uses GPU, you can find more information here. For this terminal there are lot of themes available that you can checkout on the kitty themes github page here.
You can checkout the themes with
git clone https://github.com/dexpota/kitty-themes ~/.config/kitty/kitty-themes
Once you have done that, you can use the theme with adding a line in kitty.conf as :
include <theme file name with path>