Look also at fantasy & prehistoric ranges & don't necessarily stick to 15mm (or whichever). There's quite a lot out there if you look. This is a selection of fauna from the planet Harmony, written up for a Wargames Guild competition a couple of years ago.
They're a mixture of Splintered Light, Khurasan & Green Eyed Miniatures (now at Black Hat) figures.
Terror Birds – these might not look very terrible, but these are the chicks – about 6 foot high.
Adult Terror Birds, about 15' high.
A foraging flock of Terror Birds. These ominvores eat anything.
Meer-rats. Social animals, up to 4 foot long. Live in large colonies & eat anything that they can get hold of.
Perente – large lizards, primarily carnivorous ambush hunters.
A Perente lurking in the undergrowth.
A herd of Gruffalo. Predominantly herbivores but very bad tempered & territorial.
One of the local Earth Worms.
Ants, lots of ants, giant ants
..
The local indigenies turn out to give their visitors a warm welcome.
There are two intelligent mammaloid species, living in a quasi-symbiotic relationship. They live in mixed villages & predominantly live by hunting, using tamed Gobbledock as hunting animals. Xenobiologists are unclear as to whether the two are actually related species or examples of parallel evolution. Their research is made difficult by the natives habit of killing & eating unwelcome visitors.
The natives are at a state of development roughly equal to Earth's Neolithic period. They have however been quick to adapt any bits of non-native technology that they can acquire, such as metal scraps & debris, which can be found in abundence near Colonial settlements.
The mixed villages are a combination of straw/palm huts & hide tents. The tribes are migratory, following the herds of gruffalo across the plains, but they tend to return to the same campsites every year; leaving behind them the frames of their huts for future use.
A pack of Gobbledock. They are ferocious scavengers, with a weakness for salty food. In the wild they hunt mostly by following scent trails & can be tamed to some extent, often being used for hunting. Their high pitched cry accompanys their voracious assault on any available food stuffs. As they are omnivorous then potentially anything edible is fair game. Fortunately they usually stop to eat whatever food is thrown to them, allowing their smarter prey to escape. The cry of
chippeee, chippeee in the night air chills the blood of most colonists.