None of this stuff is rocket science or anything new, but more options are always good to have, so I figured I'd throw this out there. This is what I use after the block is out of the car and transmission is off: just 1/8" thick flat stock from Home Depot w/ holes drilled through it. In the pics below I am using it to tighten the pulley bolt. If you were loosening, I'd reposition the metal or choose a different bolt hole so that it is always under tension and won't bow under load.

Jack handle + breaker bar + 19 mm socket + 1 flywheel bolt + 1 trans bolt:

 

FUNNY COZ I JUST TOOK MINE OUT COUPLE WEEKS AGO USING THE SAME METHOD..ONLY DIF IS THAT I USED ONE OF THE ENGINE STANDS ARM..

 

i find an air gun works best

 

I like a pry bar (or big screwdriver)on the started gear on the flywheel.