After I tore my achilles and spent a few weeks in a boot for my left foot, I got to be really good at shifting without the clutch.
My daughters roommate bought a VW with a manual but didn’t really know how to drive it well. I took her out and showed her a few tricks, including clutchless shifting.
She called her brother to tell her what she learned. He was the one that taught her originally and couldn’t believe her till she showed him.
My first car was a 1966 VW, and the first stick I drove a lot. After a time, I got a ‘68 van which used to break a lot of clutch cables, so sometimes I’d drive a week or two before getting around to fixing it. Just easy on the gas coming out of gear, match revs, and slip into the next gear up or down.
Once I was going mineral collecting with some friends in an older Audi, and the driver said the clutch was going out (linkage, wouldn’t disengage), so we’d have to turn back. I taught him how to shift without the clutch, and all was well. That was in the days before that stupid safety switch that wouldn’t let you start up in gear, though.