[h=5]Skills, Tools and Languages:[/h]
[h=5]Skills:[/h]Since so much about what skills will be useful depends on your stats, I'll be rating them as if they are based upon your main/secondary stat.
Athletics: Athletics is unlikely to be a check your DM asks you to make often, used mainly for trying to push, pull or break something, including yourself. So why've I rated it blue? Grapplers need this. Both Shoving a Creature and Grab require that you make an opposed Athletics check. Needless to say, proficiency really helps.
Acrobatics: Acrobatics is a useful skill. Anything from escaping a grab to trying to stay on a narrow, slippery bridge, in high winds, can be an Acrobatics check.
Sleight of Hand: I'll admit it now, I'm more of a "shoot them" guy than a framer/thief. But if you're going to plant something on, or lift something off of, someone, you'll want Sleight of Hand. Outside of those situations, not worth taking.
Stealth: Stealth is important. No seriously, even if you personally don't plan on being all sneaky, you do anyone in your party who does a huge favour. Party cooperation aside, Stealth helps you go undetected, which can result in surprised opponents and/or advantage on attack rolls. Remember: Being Hiden means you can't being targetted, and the higher your Stealth, the better chance of becoming Hiden.
Arcana: Knowledge checks, so hard to rate. For example: Does your DM make knowlege checks, or just convey information to you? If (s)he does, then this becomes Black. If you know this specific sort of knowledge check will come up, Blue.
History: See Arcana
Investigation: Oh Investigation, how scattered are thee. I've seen it used in a variety of ways, from a perception alternative, to the same except only if there's time with no passive version, to completely ignored[/color=red]. It's just not different enough from Perception really. Especially now you can have Intelligence (Perception) Checks now. But I digress.
Nature: See Arcana
Religion: See Arcana
Animal Handling: If you have a mount, then this is potentially worth it, DM dependent. Otherwise this is very campaign dependent.
Insight: Do a lot of talking? Even if you don't personally, being able to tell if someone's lying is a very good skill to have, don't want to accidently be working for the bad guy after all. You get free dental if you intentionally join.
Medicine: Good if Poisons come up, although the stabalizing bit can be made redundant by having a Healer's Kit.
Perception: Just as Stealth is vital to not getting spotted, Perception is vital to spotting things. The subtle groves of an arrow trap? Perception. The slight effects an invisible creature is having on the surrounding area? Perception. That goblin trying to hide from you? Perception. Perception, Perception, Inception. Even if Wisdom's a dump stat, take this if you've left over skills.
Survival: Following tracks, hunting wildlife and guiding people. That is what Survival covers. Situationaly useful. Free living expenses during downtime? Blue. Obviously if you don't have downtime it loses some appeal.
Bluff Deception is a good skill to have. You can convince the enemies you're one of them, the town guard that "He started it" or just act like you belong and walk right into that bad guy's base. Especially nice when paired with the ability to forge documents and stuff *cough*False Identity*cough*.
Intimidation: It's Persuasion (or Deception, there's a bit of overlap between those two), only with a higher chance of someone calling the town watch on you.
Performance: Not even By Popular Demand requires you to be proficient in Performance, only that you perform. Outside of campaign specific events, it could be used to cause a distraction.
Persuasion: There's some overlap here with Deception: If you're decieving someone with words, is that not also Persuasion? The differences are where they apply. Deception covers written notes, forged documents, maybe even conversations when you're trying to lie/mislead. Persuasion on the other hand can cover any circumstance when you personally want to, well, persuade someone.
[h=5]Tools:[/h]Not a lot here, since you can only pick up tools that were already available.
Forgery Kit: Working inversely from the background feature you probably can't forge offical documents or personal notes with this (Better if you've said feature), but you can still do a lot with unoffical documents etc.
Gaming Set:Herbalism Kit: Potions of Healing might be magical, and thus normally uncraftable. Good news! Specific vs General, and this specifically calls out that you can make them.Musical Instrument:
[h=5]Languages:[/h]Just got one thing to say: The Backgrounds with "Any Language" makes this very easy to list: