I love Koboldss because they are so weak on paper that most Dungeon Masters are going to naturally skip over these little guys the first time they bring them up in the Monster Manual, and only come back to them when they have come up with a creative way to use them. Because with a d4 damage die on ranged and mellee attacks, and functionally a d4 hit die, in a regular fight these things would be boring, even at level one. We get in the monster manual that they will use superior numbers along with their pack tactics trait and ability to accept massive casualties to overpower stronger enemies. So if you want a bunch of little dragon dudes swarming your player characters with daggers and sling stones these are your guys.
But Kobolds would rather do battle on their home turf. They are excellent tunnelers and clever trap designers: These things build dungeons. The players might think they pose very little threat after that first encounter, but fast forward and they are crawling through a pitch black, Kobold-sized tunnel (half speed if you're medium) and out of nowhere pots of burning oil start dropping from murder holes in the ceiling and pits filled with poisonous centipedes open up beneath them. Take every trap in the DMG, Xanathars Guide to Everything, Indian Jones, and Home Alone, everything you can find and have the Kobolds throw it at your party to protect their eggs and treasure.
Of course there are more trap ideas in Volo's Guide to Monsters, plus pages of wonderfully flavorful information that you can actually use while running them: Names, characteristics, social structure, goals, even a full map for a Kobold Lair. This little series has really rekindled my appreciation for Volo's. You get a couple stat blocks in there as well, the Kobold Inventor being by far the best. I reskinned Meepo in the Sunless Citadel as one when my players convinced him to travel with them and it was a huge hit. He got taken out like the T-1000 from a white dragon's breath weapon and they're still hoping to resurrect him one day.
There is also a stat block for three kobolds in a trenchcoat out there. In my world I have one (three?) who run a fight club in the basement of a seedy tavern. Good place to get that PVP out of the system. Also gamble. Yip Yip! Kobold Fight Club Baby!
That's the thing about Kobolds, in game mechanic terms and story-wise they're too weak to survive without getting creative, and collaborative. They are going to act as a group, and they are going to be willing to work with stronger forces, potentially including the player characters. They're preference would be to serve a dragon, since they're related... somehow. But the evil arch mage or the drow Matron Mothers might have enslaved them to dig their dungeons. Or the town council might have hired them to maintain and expand the local sewer system. Maybe they're cowardly little things with 5 hp, but they know every feature, trap and secret door in this mega dungeon because they installed most of them, and the party would be hard pressed to find better allies. Plus I find them fun to RP.
And if the party underestimate the kobolds and make enemies of them, these CR 1/8 humanoids might just turn their adventure into Apocalypse Now. I'm going to leave you with a link to a famous, or maybe infamous article: Tucker's Kobolds. It is a short read and if I haven't convinced you to love, or at least respect Kobolds, I'm sure it will change the way you see these little humanoids, and maybe the game itself.
