In the example below, note that some are audio only or video only.
youtube-dl -F https://www.youtube.com/watch?v=I8ik8pDTgJE [youtube] I8ik8pDTgJE: Downloading webpage'' [info] Available formats for I8ik8pDTgJE: format code extension resolution note 249 webm audio only tiny 51k , opus @ 50k (48000Hz), 1.60MiB 250 webm audio only tiny 68k , opus @ 70k (48000Hz), 2.11MiB 140 m4a audio only tiny 128k , m4a_dash container, mp4a.40.2@128k (44100Hz), 4.22MiB 251 webm audio only tiny 135k , opus @160k (48000Hz), 4.24MiB 160 mp4 256x144 144p 36k , avc1.4d400c, 30fps, video only, 507.10KiB 133 mp4 426x240 240p 64k , avc1.4d4015, 30fps, video only, 765.42KiB 278 webm 256x144 144p 75k , webm container, vp9, 30fps, video only, 965.44KiB 242 webm 426x240 240p 121k , vp9, 30fps, video only, 1.26MiB 134 mp4 640x360 360p 145k , avc1.4d401e, 30fps, video only, 1.40MiB 243 webm 640x360 360p 233k , vp9, 30fps, video only, 2.22MiB 135 mp4 854x480 480p 276k , avc1.4d401f, 30fps, video only, 2.34MiB 244 webm 854x480 480p 354k , vp9, 30fps, video only, 3.25MiB 136 mp4 1280x720 720p 484k , avc1.4d401f, 30fps, video only, 4.05MiB 247 webm 1280x720 720p 737k , vp9, 30fps, video only, 6.89MiB 137 mp4 1920x1080 1080p 784k , avc1.640028, 30fps, video only, 6.64MiB 298 mp4 1280x720 720p60 864k , avc1.4d4020, 60fps, video only, 6.56MiB 302 webm 1280x720 720p60 1068k , vp9, 60fps, video only, 9.96MiB 248 webm 1920x1080 1080p 1324k , vp9, 30fps, video only, 12.21MiB 299 mp4 1920x1080 1080p60 1514k , avc1.64002a, 60fps, video only, 11.66MiB 303 webm 1920x1080 1080p60 2000k , vp9, 60fps, video only, 17.48MiB 22 mp4 1280x720 720p 247k , avc1.64001F, 30fps, mp4a.40.2@192k (44100Hz) 18 mp4 640x360 360p 262k , avc1.42001E, 30fps, mp4a.40.2@ 96k (44100Hz), 8.71MiB (best)