I found it very helpful to collect great reference for animation topology.
Here i go over some of my process for retopology, hope it is helpful.
First I take a couple notes on the existing model i created for where the most significant areas that need better topology (this was extremely helpful to do before began re-topologizing because it allows to see the whole model at once versus when start working out technical details its easy to get lost with all the poles etc. ). Then going over with another pass trying to correct topology.
Here's an example of my beginning topology note taking process.
I found it very helpful using edge deletion to reroute edge loops because it kept the general faces so could still see shape of mesh.
I also found it really helpful given i worked out some preliminary topology for a quadruped to then reuse this topology on another original character i designed and modeled. In ZBrush it was helpful making a shortcut for ghost mode.
Using ghost mode in ZBrush can fit topology mesh to rough no
animation topology mesh. Here I mainly used move,rotate, and scale tools with
lasso mask and the smooth brush. I sometimes reduced intensity for the smooth and brush for when i wanted to move things by alot or by a little.
using xray mode sometimes helpful when lots of edges needed to be reworked
blocking in a rough eyelid area by working only on this part of head. I can imagine can reuse this eyelid topology when its done so don't have to remake eyelids every time.
in Maya, soft selection with scaling is really helpful to block out volume of shapes.
Here's a look at some of my note taking process after first rounds of retopology for my original character Flexy.
Attakarn Vachiravuthichai ( artbyatt dot com )