I watch A LOT of TV...
I've test ran a handful of free fonts for my subtitles, and Tiresias Infofont Z so far is definitely my favorite.
Included below is (part of) my mpv configuration, that really makes the font pop. My vision is quite poor without my glasses, but I can read these very well without them.
sub-blur = 0.3
sub-border-color = 0.0/0.0/0.0/0.8
sub-border-size = 2.5
sub-color = '#FDFD9A'
sub-font = Tiresias Infofont Z
sub-font-size = 42
sub-margin-x = 100
sub-margin-y = 50
sub-shadow-color = 0.0/0.0/0.0/0.25
sub-shadow-offset = 0
