The individual mandate was upheld by the SCOTUS in 2012: https://en.wikipedia.org/wiki/National_Federation_of_Indepen...
Rather, the individual mandate was zeroed out in 2017: https://en.wikipedia.org/wiki/Tax_Cuts_and_Jobs_Act_of_2017
The Cadillac tax has been delayed, seemingly indefinitely: https://en.wikipedia.org/wiki/Cadillac_insurance_plan
The employer mandate was delayed.
The Independent Payment Advisory Board was canceled: https://en.wikipedia.org/wiki/Independent_Payment_Advisory_B...
The nutrition labeling requirements were delayed from 2010 to 2018.
There are many other more technical provisions that have been delayed as well. It is easy to find many relevant sources online, though it's hard to keep them up to date because many delays just continue! https://cgsnet.org/ckfinder/userfiles/files/ACA_Delays_at_a_...