I don't think spiders, birds, snakes, frogs, and rats would look good or believable as particles, and while fish could work, the particle would eventually have to disappear before emitting a new set of particles
Butterflies could work, but it would still look awkward, particles can animate (for a fluttering motion), but they can't loop, and they'd be flying around aimlessly or flying through walls or the floor
I don't really know what to do about a candle/torch fire besides a fire with a staggering emission rate
Water drops and splashes are possible, but that can also be done with projectiles,
like Muffinmix's rain physics, except optimized, so instead of creating a dozen debris, it could just emit particles in a circular pattern where the projectile impacts
I'm not sure how one would make a particle that makes things look wet
As for mist, Fog B looks pretty mist like
floating dollar bill particles
B)
It's raining money!