OpenShot
Shotcut
http://www.pitivi.org/
https://www.olivevideoeditor.org
kdenlive.org
Blender
https://www.lwks.com

Linux only
https://jliljebl.github.io/flowblade/
http://cinelerra.org/

Side by side video ffmpeg :
ffmpeg -i ZeldaTPOriginalResolution30FPS_640x528.mp4 -i ZeldaTPOriginalResolution30FPS_2560x2112.mp4 -filter_complex hstack -c:v ffv1 sidebyside.mp4