a bit of a warning: These terminals are designed with *NIX in mind (Linux, BSD, Mac OS) so if you don't use one of these operating systems then this list might not be for you. (Do windows users even need terminals?)
Good minimalist terminals to try out
urxvt:

urxvt is a simplistic yet powerful terminal that is also very customizable. You can change it's appearance using .xresources.
suckless st:
st (simple terminal) is an extremely lightweight and minimal terminal made by the suckless team. It follows the suckless philosophy meaning by default it's barebones but can be turned modern and complex using patches.
alacritty
alacritty is probably the most popular on this list, it's quite minimal but very customizable using it's own .yml config file. It also utilizes the GPU. Many people dislike this terminal as they consider it to be bloat.