The following is a list of genera of the most commonly collected tarantulas in the private owner community. Knowing at least one species from each genus will help you identify the different species that you encounter among private keepers. I encourage you to focus on learning genera and not species because you will cover a lot more ground than learning all the species of one genus.
Acanthoscurria
Aphonopelma
Avicularia
Brachypelma
Bumba
Ceratogyrus
Chilobrachys
Chromatopelma
Euathlus
Eucratoscelus
Grammostola
Hapalopus
Haplocosmia
Haplopelma
Harpactira
Heterothele
Holthele
Hysterocrates
Lampropelma
Lasiodora
Megaphopelma
Nhandu
Ornithoctuonus
Orphnaecus
Pamphobeteus
Pelinobius
Phlogiellus
Phlogius
Phormictopus
Poecilotheria
Psalmopoeus
Pterinochilus
Selenocosmia
Sericopelma
Tapinauchenius
Theraphosa
Thrixopelma
Vitalius
Xenesthis
It is not the one without mistakes, its not the one without regrets, it is one who never gives up.