OBS (Open Broadcasting Software)
Fix flickering in screen recording w/ Bumblebee (on laptops) or w/ Intel driver only
KDE: go to system settings > Display and Monitor (at bottom) > Compositor > Tearing prevention ("vsync"): never
(similar options in the (window) compositing menu in GNOME, XFCE, etc.)
If you see some windows/toolbars flickering, reboot or alt+tab a bit to fix the issue.
If you want to re-enable it when done, go back and set it to "Automatic" (what I had it on)