Reflectors
In addition to diffusers, there are reflectors that reflect light onto
your subject. Diffusers allow light to pass through them and you
hold them in between the subject and the light source. Reflectors
are held off at some angle to reflect light on the subject. I have tons
of them but I mostly use them for video studio work. They can be
helpful outdoors in taking macro shots where you are in the shade
and trying to get more light on whatever you are photographing.
Still Other Thoughts:
Stacking Live Critters
Live critters do sometimes hold still long enough for stacking.
Spiders, bees in the early morning, you would be surprised. Ants?
Not likely. Butterflies yes and definitely dragonflies. Try for it. You
will be surprised what even a two-shot stack will produce in terms
of greater focus depth.