My Take on a Human Variant Rogue/Warlock/Bard Skill Monkey build
8/14/13/13/13/15 point buy-
1st lvl Rogue - 4 Skills + 2 Background + 3 from Skilled Feat + 1 Human = 10 skills ( 2 Expertise skills)
2nd Lvl Warlock 1 = 10 Skills (2 Expertise Skills)
3rd Lvl Warlock 2 - (Beguiling Influence (Deception + Persuasion)) = 12 Skills (Also take Devil Site 120' Dark Vision takes away from the weakness of being Human)
4th Lvl Bard 1 - Performance = 13 Skills
5th Lvl Bard 2 - 0
6th Lvl Bard 3 - Lore Bard + 3 Skills = 16 Skills (4 Expertise Skills)
7th lvl - 20th lvl Rogue 15th lvl = 16 Skills (6 Expertise Skills) + Darkvision 120' + Resilient Feat (Charisma)= 4 Good Saves (Dex, Int, Wis, Cha)
The two skills you don't take will be 2 or 4 by 20th depending on your stats. The lowest skills will be around +7, but your expertise skills will be +15 or +13 depending again on your stats, that's 1/3rds of your skills have expertise.