Here are two creatures from an upcoming illustrated book Leviathan from Scott Westerfeld and I.
The Entente powers in this alternate history have made such massive inroads with Darwin's discoveries that they now structure their whole societies on genetically modified animals custom bred for specific applications.
These are Lupine Tigeresques, being used by the Navy to pull an armoured carriage for an inspection.
This is a Huxley Ascender, a jellyfish creature used for recon and signaling by the Royal Air Navy.
In contrast, the Central powers have raced down a heavy industrial path and use huge walking mechs to square off against these creatures in WWI. Here's a trailer for it: