The 3-headed dog the dude had to fetch from the gates of Hades.
Cerberus (12th)
The rivers Alpheus and Peneus had a lot to do with this 5th labor.
Cleaning the Augean stables
Maybe we should thank this cousin of Hercules who set these tasks and gave us so many adventures to read.
Eurystheus
When Hercules was cutting the heads of this beast, Iolaus helped him by cauterizing the open stumps.
The Laearnian hydra
The 2nd labor - he had to slay this beast that kept sprouting heads.
(Lernaean) hydra
7th labor - he was compelled to capture this bull on an island as his seventh task.
Cretan bull
Originally, Hercules was tasked with only ten labors but these two were not counted as he took help.
Killing the Lernaean hydra (and) cleaning the Augean stables
The 3rd labor in which he had to capture this swift beast sacred to Artemis.
Ceryneian hind
In this 9th labor, he impressed an Amazonian queen with his muscles and she just gave him what he wanted - this.
Girdle (of the Amazon Queen)
10th labor - he was required to travel to Erytheia to obtain these bovines.
Cattle of Geryon
It all started with him killing this beast whose fur was impenetrable to arrows.
The Nemean lion
His 4th labor in which he had to capture this wild pig.
Erymanthian Boar
8th labor - capture the man-eating horses called Podagros (the fast), Lampon (the shining), Xanthos (the blond) and Deinos (the terrible) whose madness was attributed to a diet of human flesh.
Mares of Diomedes
6th labor - he used bronze clappers to scare these birds and then shot them as they flew away.
Stymphalian birds
In this penultimate labor, he tricks Atlas into carrying the skies.
Steal the apples of the Hesperides