By survival I mean not dying in combat. Doing more damage etc are all lesser considerations, as is keeping concentration spells up. It of course can also help win battles, a good offensive and all, but the main point is not to go down when opponents focus on him and decide to take him out

This is a good list, but it's more of a "what feats are useful for a wizard in general" list, not that much focused on not getting killed. E.g. Elemental Adept looks like a mostly offensive option that will not do much to increase their survivabiltiy other than by killing some foes faster.

Inspiring Leader is an interesting one. I think it will not make a difference for our group due to the divine caster's Aid spells, but I could see that as a nice pickup otherwise.

@GroodytheHobgoblin, does "not dying in combat" mean being hit less, or taking more hits? Does it mean not being where the combat is? Does it mean getting hit, but either reducing or nullifying damage? Does it mean putting the attacker out of commission so they can't attack? There are, to coin a phrase, 101 ways NOT to die in the west. And what will work for you, may not work for a different group.

Aid increases your max hp, so temp hp will still stack on top of it.

@MivaScott: whatever achieves the goal. Can be taking less hits, can be surviving more hits. The question is if you are to pick a feat, which one to pick and why? Is it possible to quantify, even aporoximately? It’s not about taking the attacker out fast, I added that to clarify

@GroodytheHobgoblin the point is that all of the feats listed above will increase the survivability of the wizard. We can give you a single specific feat if you can give us a single specific metric, which you haven't. If it's just maximizing HP, then it's obviously Tough. But there is so much more to survivability as a whole than just maximum HP, so we cannot say that Tough is best for survivability itself. It depends a lot on what specifically you're trying to survive: Melee attacks, spells, falling off a cliff, not having the one concentration spell keeping you alive broken, etc.?

@GroodytheHobgoblin I see how your metric is objective from your perspective. The problem is there are many ways to affect it, that are not strictly ordered. That is to say, you can't say "A > B > C". You can say that only with relation to specific playstyles and situations. You may as well ask "which is better, napalm, tear gas, or a sniper rifle?" It's the same thing; you can easily define a simple metric to be 'better = fewer deaths', but that still doesn't make the question answerable. The answer is 'it's situational'. How, exactly does your wizard plan to stay alive?

@TonDay, yes. The problem is, I do not know what the challenges or situations will be. I'll adjust the question to ask about play experience with the different feats, that may be a better way to go about it, and get people off from the natually impossible task of a mathematical proof of superiority to making an informed choice.

That's still going to be problematic. I see something here @MivaScott didn't list, and that is Skill Expert (Intimidate). How does that improve survivability? I AM OZ. THE GREAT AND POWERFUL. PAY NO ATTENTION TO THE MAN BEHIND THE CURTAIN! (rolls dice) "The enemies decide maybe they don't want a piece of you after all; they just ate. They leave."

How do you figure that in numerically? Someone could sit down and try to analyze the impact that taking that feat would have on the number of times you would succeed in intimidating folks to leaving your party alone, where without it, a fight would have broken out. But that would still be abstract. It's difficult to apply to your campaign without more. And then the next problem is, how does the reduced number of combats impact the lethality of the game? That's essentially impossible to quantify, since if you never actually fought somebody, you don't know how deadly they would've been.

@TonDay, yeah, our DM is not going to let that work. One player even changed (with DM OK) away from Persuastion, as it was no use in play. Assume that there will be combat and ambushes. But I see the issue.

@MivaScott: Due to all the blowback for wider feat selection, I will narrow the cirteria down to just a handful of feats I am really interested in, I apologize, as this will make your answer not a good fit.

@GroodytheHobgoblin, In which case, it may be better to create a new question

@MivaScott As I understand it, that it not what I am supposed to do. See this meta: rpg.meta.stackexchange.com/questions/6324/…

@MivaScott: The OP mentions that the Wizard has a Charisma score of 14 (may have been edited), you may want to edit your advice on Inspiring Leader to take this information into account.

@MatthieuM., That fact was edited in WELL after my original synopsis. As you'll note in the comments above, the question got changed/refined to a point where this answer would almost make no sense. But I wanted to keep it around for historical reasons. But to your point, I fixed IL to show 14 hp instead of 13.

@MivaScott: I suspected so, and I agree that keeping the list of feats makes sense, just thought you may not have noticed that the OP had specified the character's Charisma, which makes things more concrete :)

I have downvoted this answer because it is mostly a list of options, rather than a which is better. Little attempt is made to analyze the options and it ends with a platitude. Suggesting that for example 'Lightly Armoured' is a good feat choice for survival (it lowers your AC without magic armour) in order to 'save' a 1st level spell slot (at level 12 a Wizard has 16 spell slots, and 1st level ones are the least useful by far) is a very poor attempt to answer this question.

@TonDay Experience. If you have spent time learning about the common styles of game, and can infer things about which style this character is in from the question ('old school') the likelihood of being able to Intimidate the character's way out of an encounter can be computed, albeit with considerable margin of error. 5e has a very limited number of feat options, and enemies generally conform to specific types. The amount of comparison to consider most reasonable choices is not impossible at all.

@user2754 - If you read the comments, this answer was put up with the original version of the question. The question morphed making this answer no longer correct (details added, greatly reduced allowed feats, etc.).. But I left this up here as it was valid and well thought out. I guess I should put a warning to prevent these kind of responses in the future.