/effect @p 8 999999 255 negates fall damage. However if you jump as you take damage you jump higher than 1 block you jump about 60 blocks instead. Things I have tested so far and have behaved like this are ender pearls, fire, cactus, lava, poison, instant damage, tnt. How it seems to work is if you are in midair after a jump it launches you (only after a jump, if you walk off blocks it doesn't work). Fire and poison launch you even higher as you take more damage after the jump.