Re: back ideas
ghr's and extensions are great accessory work. reverse hypers are awesome as well.
deads and their variations are great, (pin pulls hit your back more) depending on the goal. lets not forget ghr's, reverse hypers, etc are all mainly directed to be heavy on the hams/thighs, ass, erectors, etc ie. squat muscles.
dont forget kroc/dumb bell rows, pendlay rows, bent over rows, chins, t bar rows, rope pull ups, inverted rows.
facepulls, shrugs, rope pulls to throat, band pull aparts are great upper back accessory work, particularly if trying to increase your bench.
just like anything, all depends on the goal. strength, mass, etc