S-Tier: Take these if you can.
1. Perception: Solve mysteries & avoid traps & thwart ambushes.
2. Insight: "Tell me what this NPC is REALLY thinking."
A-Tier: Pretty good.
3. Persuasion: "I tell them to be my friend."
4. Deception: "I tell them to be my friend, but I'm lying." Riskier than Persuasion, but roughly equivalent. Bad rolls on this often lead to more fun than good rolls, but good rolls build tension.
5. Athletics: Necessary for climbing/jumping/moving big things out the way, and useful for grappling.
6. Investigation: Insight for the environment.
B-Tier: More rarely used, but pretty good.
7. Stealth: A must-have for the party, but really only something one character needs, and even then scouting is a risk.
8. Arcana: Most useful of the knowledge skills; a lot of DM's treat this like "detect magic lite."
9. Acrobatics: A useful alternative to Athletics when grappling, but otherwise a pretty pointless skill. "Do a backflip" doesn't solve many problems.
10. Sleight of Hand: Sometimes used for picking pockets or locks, but needs some pro-active use. Never really necessary.
C-Tier: Toss-up. You don't need these, but you might get some use out of them.
11. Animal Handling: Persuasion, but for things that don't speak. A campaign can ignore this for the most part, but when it's useful, it's useful.
12. Survival: Some campaigns can completely ignore this skill, but others might use it quite a bit. So C-tier: useful when it's useful.
13. Nature: Reasonably useful knowledge skill for "what that monster do?" But like other knowledge skills, can be useless depending on the DM.
D-Tier: Mostly a trap.
14. Religion: Marginally useful knowledge skill for like angels and devils and stuff.
15. Intimidation: Depending on DM, either a "start this fight" button or a "make NPC do exactly one thing and then nothing else" button.
16. History: Marginally useful knowledge skill for when the DM has put extra work into the lore and for some reason that's important.
Super Hell: Why are these even skills?
17. Medicine: Everything comes back on a long rest. Sometimes marginally useful knowledge skill for "how did this thing die?" but Investigation does that work, too. Could be useful in a game where injuries linger.
18. Performance: Main use is for "how did I do with my song?", which in practice is an OK bit of RP, but, like, why are we rolling for this? There's not usually consequences for doing well OR poorly, so idk, just tell me what you do.