Ultimat skill monkey! (All proficiencies by lvl 9)

[Lacka]

“If you would like to have the spotlight whenever it comes to skill checks this build is for You my friend”

So this build get’s you all 18 proficiencies whitout wasteing ASI-s on anithing like that (to be fare you barely get any with this build :D )

Tl;dr
Half-elf: 2
Background: 2
Rogue: 4 (+ 2/4 experties)
Rogue/scout: 2 (nature + survival experties)
Lorebard: 4
Knowledge cleric: 2
Warlock Beguiling Influence: 2 (decepcion + persuasion)
Sum: 18

Scout3/lorebard3/knowledgecleric1/warlock2 = 9

On a longer note:

I grabbed all the low hanging fruits for this build from all over the place.
This means your character is spread out real thin but knows it all.

By RAW multiclassing has some stat conditions to met:
Rogue: Dex 13
Bard: Chr 13
Cleric: Wis 13
Warlock: Chr 13
(Ranger: Dex 13 + Wis 13)

You have to do some thinking before takeing proficiencies so you dont end up cuting yourself off from one.
Things to bare in mind:
Rogue can’t take Arcana, History, Nature, Religion, Animal handling, Medicine or Survival
Scout gives experties in Survival and Nature
Knowledge cleric can chose two from Arcana, History, nature and Religion (dont take Nature because of scout)
Warloc invocation gives Deception and Persuasion


Nice, but where next?
For final builds you have a lot of options, here are my favourites:
The EXPERT: If you came this far why not go all the way!
Bard10/Rogue6/Cleric1/Warlock2: picking up the grand total of 12 experties on the way! (4 Bard + 4 Rogue + 2 Scout + 2 knowledge cleric) Last lvl to Rogue for evasion, to warlock for pact boon or to Bard for 6th lvl spell
This also gives 3 ASI-s
Steady hand: “Trust me I realy do know what im doing...”
Rogue11 for reliable talent for an at leat average outcome.
Up to 5 ASI-s (chose 2 from: Rogue 12 / Bard 4 / Warlock 4)
Songbird: “I can do this while singing!”
Bard14/Rogue3/Warlock2/cleric1 picking up peerless skill (with d10) and a lot of bard goodies up to a lvl7 spellslot.
3 ASI-s
I serve the Old One: “Not even this much knowledge can understand It”
Warlock13 for a 7th lvl spel and more Warlock awesomeness
3 ASI-s

Might work: Multiclass into anything but Barbar, Paladin or Wizard (to avoid absolute MAD-nes)

I don’t recommend going for more Cleric lvl-s because I dont like clerics ( also channel diviniti is not that good)
Only reason to go for this is if you talk to your GM so channel divinity gives experties for alredy proficient checks! ;)

And where do I fit in?

A Social God! (With extras)
http://www.giantitp.com/forums/showthread.php?490505-The-Social-God-A-guide-to-an-optimized-party-face

A slightly less eficient caster?

A basher! (Just for fun):
Picking up Athletics experties , shildmaster (and maybe an extra attack) and run around knocking people prone :D

These ideas are just guidelines, I bet you can make even better things with this, but I hope I started something in You!

Thanks for reading!

Lacka

[Vessyra]

Variant human with the skill mastery feat, (+1 skill variant human, +3 skills feat), level 1 rogue (+4 skill), lore master bard 3 (total +4 skills), background (+2 skills), knowledge cleric 1 (+2 skills). With proficiency in all skills, I then take one more level in bard and three more levels in rogue so that I can spend my ASI's on those unearthed arcana feats that give you expertise. Then I throw in guidance for good measure

[Boverk]

Yeah, it can get pretty crazy. If UA is allowed, Half Elf Rogue Scout 13, Lore Bard 4, Knowledge domain cleric 1, Lore Wizard gets proficiency in all skills, and expertise in all but 2 (Medicine and Animal Handling for example). It does require a couple of the UA Skill Feats (Menacing and Performer) and the half elf UA feat Everybody's Friend.

Without UA, Half Elf Rogue Scout 13, Lore Bard 6, Knowledge Cleric 1 gets you prof in all skills, and expertise in 11 skills. With point buy, the worst skill check this build will ever do is 18. I think it requires the skilled and prodigy feats.

There is also a bit of flexibility with the last 3 levels of life bard. They could really be anything.

[Foxhound438]

I'll reiterate that that you can save a whole class somewhere by starting Vuman for 4 skills at the cost of slightly greedier stats, but you save the need to take a class that only gives you 2 skills. Unfortunately you're still in 4 different stat needs when you account for con, but you can probably get away with it by having stats like 8/14/14/8/13/16 and using medium armor from cleric or ranger.