neck

https://www.youtube.com/watch?v=bu7Az5w2ttM&t=300s [Embed]
before anything if you are new to neck training do these exercises, after a while you can put a small weight on your head and do these same exercises, a harness is completly unnecessary, but can be useful, how ever doing them like this
https://www.youtube.com/watch?v=VDIMs32wHPI [Embed]
can be more beneficial since you also train your jaw and you can also do the same exercises of the same video plus standing exercise with either this method or a harness
these are pretty much what you need for a strong big neck, you don't need to do bridges since some flexibility is needed in the spine to not hurt yourself doing bridges but if you do have the flexibility after doing the first two videos for a couple of months you can add https://www.youtube.com/watch?v=W_R5W0Apc_U [Embed]
for an even better development,
deadlifts and shrugs do not affect your neck muscles at all but be sure to train your trap along with your neck for better aesthetics
https://www.youtube.com/watch?v=q7MCjaJ02eQ&t=643s [Embed]