The Walking Dead has lately had a major problem, and that is that it has way too many characters. It's great to see different communities, but we've lately seen episodes based around characters we don't care about and major characters not getting enough screentime. I believe Season 8 will use war as an excuse for population control and kill off many main characters. Here is a list of who that will and will not be.
(This list is based 100% of personal opinion and should not be relied on. No confirmed TV spoilers and very few comic spoilers will be used.)
Morgan- Morgan has went from clear to not killing to clear again and I believe he may die this season during war saving King Ezekiel or Carol.
Judith- I believe that the show won't want two babies with Glenn and Maggie's coming, and the Saviors killing Judith could motivate Rick without destorying him.
Carol- With her snapping back into Warrior Carol after moping around for a season, I think the writers may decide to kill her off.
Tara- Tara has gotten a scary amount of screen time lately, and she may die during war, possibly in a heroic way.
Gabriel- Gabriel has changed a lot lately, and as he starts developing at a rapid rate, the writers might kill him off.
Eric- Eric has also gotten a lot of screentime lately with our main group and he may die during war.
Tobin- Tobin has become a semi-useful member of the group and he may die helping someone or sacrificing himself.
Multiple Alexandrians- Of course, it would be unrealistic to only kill characters who have had screentime.
Simon- Negan's right hand man may sacrifice himself for his boss/partner/wife/whatever Negan calls him.
Jared- I could see Jared getting killed by someone from the Kingdom after everything he's done to them.
Gary- I believe we need Savior deaths and he will be one of them.
Harlan Carson- I believe Harlan will refuse to work for Negan and be killed.
Kal- Kal will probably die in war either fighting or sacrificing himself.
Gregory- I believe that when Gregory finds out about the war, he will become afraid and try to help himself by flying to the winning team which he believes is the Saviors. He will try to sway Negan but get himself caught in some lie and be killed by him.
Jerry- Despite him being one of the greatest characters in television history, I believe he may serve as one of those deaths that snaps a character (in the case probably Ezekiel) into killing mode.
(To explain these next predictions, I believe Oceanside will join the war at some point)
Natania- Natania may become scared and give up with the war, getting herself killed.
Beatrice- Beatrice will probably sacrifice herself for Natania or Cyndie at some point.
Jadis- I believe the Scavengers will fight for Negan and Rick will kill Jadis, convincing her group to flee and hopefully never be heard of again.
Shiva- With CGI costing a ton of money and Shiva's expenses ruining other CGI moments, *coughDEERcough* I think Shiva will die this season.