If you are looking to buy a classical curriculum with everything you need that comes to you all in one box (at a reasonable price!) then look no further: The Memoria Press Classical Core Curriculum Set

Classical Core first grade curriculum
Classical Core First Grade Complete Set

But if you are more eclectic and prefer to piece things together yourself, here are my best recommendations:

Supplements:

Primary Phonics Readers (Sets 2-6)

Read-A-Louds

*Denotes hardback

The First Grade Supplemental Science and Enrichment Set includes all books listed below: