Online Curriculums

Free Curricula

Easy Peasy All-in-one Homeschool
Ambleside Online
Connections Academy
K12
MIT Courses

Paid Curricula

Online curriculum

Time 4 Learning
Legacy IOHS

Traditional(using textbooks) curricula

Calvert Education

Variety of Courses

Khan Academy (all grades, free)
cK12 Courses (all grades, free)
Open Culture (free)
EDX Courses (free and paid)
Universal Class< (paid)