Goblin King. I made a suggestion about this before maybe, but Ive developed the idea a bit. It could be a turn based strategy tile grid game, or even done as a more thoughtful settlers ish RTS
You start with a small clan. Goblins are in a weak state. The world is full of humans and the wild game is increasingly rare, with once free land turned into farms. Human soldiers have relentlessly driven you further into the margins of the world, into the caves, living from rats and mushrooms. But this ends now. You will lead the rebellion and state a claim to a goblin kingdom, you as it's king. But first you need an army.
You start with a very limited number of units. The humans on the map outnumber you, and if they learn of your location will send armies to wipe you out.
The basic resource is food. Your first job in the initial phase of the game is to keep the food coming in so that you can recruit/spawn more units and keep the ones you have alive. You need to stay hidden while scouting for food sources and threats, moving your camps strategically to bring them to food and out of the way of harm. Raiding a small village far away from you based may help to distract and draw away unwanted attention from elsewhere.
In the second phase you gradually shift into proper guerrilla warfare with the units you have made, striking quickly and then withdrawing so as to avoid direct confrontation with a still far superior human army. You amass weapons, take whole towns for livestock and slaves, and discover and recruit other beasts with a grudge against your opponent. Trolls, wolves, etc.
Finally you have all out war, and the challenge of when to time the revealling of yourself and strike. Too soon and you will be crushed in the field. Too late and your gathering armies may become unstable for want of food and fighting. Which cities you strike when will also be an important choice that depends on information gained so far with scouting.
Through it all you have to be careful not up let the hero captains of the humans find and capture your own unit, or all is lost.