$ for c in $(ffmpeg -v error -encoders | awk "{ print \$2 }"); do ffmpeg -v error -h encoder="$c" | grep -q "Threading capabilities: [^n]" && echo $c; done
libaom-av1
vc2
dnxhd
dvvideo
ffv1
ffvhuff
h263p
libx264
libx264rgb
libx265
huffyuv
libopenjpeg
jpegls
ljpeg
magicyuv
mjpeg
mpeg1video
mpeg2video
mpeg4
png
prores
prores_aw
prores_ks
tiff
utvideo
libvpx
libvpx-vp9
zlib