Caterpillars are not easily seen, and I know no way of identifying them, other than capturing them, keeping them, and waiting to see what they turn into. I haven't had the time for that, I'm afraid. Here are photos of the few I have seen.
Silkworm (Bombyx mori)
Atlas Moth (Attacus atlas)
Common Crow (Euploea core)
Tussoc Moth (Calliteara horsfeildii)
Common Mime (Papilio clytia)
Deaths-head Hawkmoth (Acherontia lachesis)
Oleander Hawkmoth
Lappet Moth (Gastropacha sp.)