I like kobolds (if you want, you may read others articles of mine about them).
If you want to inject some random craziness into your game, use the chart below.
I've modified a similar chart for D&D 4e by Mike Mearls, originally appeared in Dragon 364.
When a kobold drops a creature to 0 hp roll a d12
1 Take the stuff and run away
2 The tribe will shine
3 I was only lucky
4 That's never happened before
5 I'm better than you
6 Let's win the fight
7 You're next
8 This will only anger them
9 I'm only getting started
10 I'm the strongest warrior of the tribe
11 Time to run!
12 Fear Me!
The kobold gains 2d6 temporary hp, has advantage on saving throws and attack rolls and add 1d6 to its damage on successful weapon attacks.
I'm better than you
The kobold can use its reaction to cast the vicious mockery cantrip targeting another hostile creature. Charisma is its spellcasting ability and the spell save DC is 10.
I'm only getting started
The kobold gains 2d6 temporary hp.
I'm the strongest warrior of the tribe
The kobold can immediately take another Attack action rolling weapon attack with advantage and adding 1d6 damage on a successful hit.
I was only lucky
The kobold can take the Hide Action as a bonus action until the end of its turn.
Let's win the fight
The kobold use its reaction to make an inspiring speech. All kobolds that can hear it within 30 feet add 1d6 damage on a successful attack until the end of the fight.
Take the stuff and run away
The kobold picks an item from the fallen creature and can use its reaction to take the Disengage Action and move away up to 15 feet.
That's never happened before
The kobold is stunned until the end of its next turn, shocked by its own success.
The tribe will shine
All kobolds that aren't unconscious within 30 feet gain 2d6 temporary hp.
This will only anger them
In fear of retribution of the creature's allies, the kobold is frightened until the end of its next turn.
Time to run!
The kobold can take the Dash Action as a bonus action until the end of its turn. Its movement doesn't cause opportunity attacks.
As a reaction, the kobold can move up to 15 feet and make an attack to a creature that is hostile to it.
Born to be Kobold!