for rotifers, cladocerans, copepods, the best one is: http://www.mdfrc.org.au/bugguide/resources/3-1995-Shiel-Guide_to_rotifers_cladocerans_copepods.pdf:
freshwater or marine? Basic or complete? what continent? I suppose, you mean Rotifers, Copepods, and Cladocerans. If serious, so use Kutikova for Rotifers all-world, but it is in Russian. Manuilova for Cladocerans, Smirnov for Chidorids etc. Lang for Harpacticoids (Lang K. Monographie der Harpacticiden. – Stockholm : Nordiska Bokhandeln, 1948. – Vol. 1-2. – 1682 p.) but is it necessaryBetter to use taxonomical guides as a lot of species can inhabit both bottom and pelagic biotopes, esp in fresh-water. For.i. For fresh-waters harpacticoids inhabit bottom, and in sea littoral and plankton! Therefore, please, precise the group and biotope
For any case I'm attaching Kutikova id. key for high saprobic conditions.
I have found by looking and researching collages and hierarchical data sets of Zoo Plankton to be found in three different locations; http://flocculate.missouristate.edu/zooplankton/ & http://marinebio.org/oceans/zooplankton/index.aspx & Pictures of actual live specimens: http://georgiaseagrant.uga.edu/images/uploads/media/Zooplankton_key.pdf I hope this helps !!
This is a general black & white guide that works for many species in most ocean environments -- http://www2.sunysuffolk.edu/blackn/UCLAplanktonIDguide.pdf
This one has nice microscopy photos of zooplankton, again from southern California USA (Pacific) -- https://scripps.ucsd.edu/zooplanktonguide/