On Venusians:
CO2-fixing bacteria & aeroplankton
On Martians & Lunars:
antifreeze bacteria (to melt ice)
purifying bacteria (to remove antifreeze)
On Aquatics:
floating barnacle colonies
symbiotic systems of diving weeds & sea-fungi with abyssal fungi, (transfering energy down and nutrients up)
Miscellaneous:
dark green, high-O2-producing weeds & mosses & "pines"
colonial "crabs" (ant-sized crab-like arthropods of very flexible behavior, in several species, many of them exhibiting ALL the tricks of hymenoptera)
"thebiks"/"octopests" (tiny terrestrial octopus-like echinoderms)
"struthioids" (relatively rare animals like furry ostriches – two-limbed, beaked, often hermaphrodite/androgyne, oviparous or ovoviviparous, multiple fixed-focus eyes sometimes stalked or swiveling)
Produced by genetic engineering, mostly before the arrival of the New Terraformers (and sometimes imported in transgenic form from the Old Ecumene), for domestic use, or for game animals, or for biodiversity, but some produced as weaponry in the Terraforming conflicts.
Many duplicate the riding, driving, draft, and dairy functions of horses and cattle. These animals may simply have been fashionable alternatives, or may have come from worlds where the settlers brought no such animals with them and were unable, for reasons of economics or politics, to get them.
Felines:
miniatures
ferretines
bob-cats-sized retrievers (as in ancient Egypt but bigger)
approximate recreations of Terran big cats
giant tabbies (panther size)
tigons, pard-lions
multicolor lions & tigers, including blond, point, black, & white lions
[most remain fairly domestic/feral in behavior; leonids only approximate original pride/pack behavior at best (based on neurology transferred from dogs)]
Canines:
wolves (very close to original)
fox-dogs
maned lion-dogs
giant draft dogs
giant attack breeds
hi-speed attack breeds
dairy breeds
riding breeds
"wool" breeds
mouse-sized miniatures
Caprids (Sheep & Goats):
dairy breeds
draft breeds
riding breeds
wide variety of wool colors
parthenogenics
meat-casters (giving regular "birth" to masses of muscle tissue)
Swine:
high-intelligence pet breeds
driving breeds
draft breeds
meat-casters, sometimes parthenogenic
attack breeds
Rodents:
giant hell-rats
morses (horse analogs)
moxen (ox analogs)
retrievers
squirkeys (pets - large squirrels with prehensile tails & high intelligence)
Fowl (Chickens & Turkeys):
ornamentals
moa cocks (struthioids, ostrich analogs)
Tyrannogallus rex (the Thunder Chicken)
hunting fowl (falcon analogs)
parthenogenic laying breeds
Atanidae (Ducks & Geese):
giant barge-pulling breeds
parthenogenic laying breeds
painted swans
gullards (gull analogs)
ducquins (penguin analogs)
balards & delphards (fully aquatic whale and dolphin analogs) ("moby duck")
schoons (giant aquatic swans combining features of plesiosaurs & sailing ships, with wings as sails)
Catfish:
giant & ornamental breeds
Carp:
giant & ornamental breeds
Hymenoptera:
ornamentals
specialized honey-makers, paper-makers, wax-makers, silk-makers
high-venom attack wasps
Lepidoptera:
Ornamentals: giant, miniature, swarming, luminous
Silk-makers