The struggle is real! Here are some I've found [time4learning.com], [freereadingprogram.com], [discoveryk12.com], [xtramath.org], [prodigygame.com], [mobymax.com], [secularhomeschool.com]

I know there are secular homeschool and parenting groups on Facebook. They may be helpful (until our community here is larger).

Make your kids aware that others hold beliefs that are important to them, even if they are as irrational as the Easter Bunny, because they are scared. Give them an education that includes mythology along with and explanation of how these beliefs got started. Why would you include just one god when there are so many, which are quaint and fun to know about and that none of them are real.

Well I do informal science education as my career, so I am literally devoting my life to teaching kids how to critically think. I can't think of any specific resources, but I tend to look up resources as needed.

Home schooling don't know.... Secular parenting, that I know. Two daughters, both brought up with no religious crap at home but they were always told they could choose whatever the heck they wanted and we (parents) will not have a problen with it. My youngest at 12 engaged with a church just to follow a friend and dragged me into it. I played along until she understood by herself its all BS. Long story short, both turned out ok so far... No Gods and yet good values as a person

Dude! I've been researching secular curriculum for years now. Let me pull up my bookmarks and get back to you.

Public libraries or the would-be public school may share some material. My children were in early elementary when I homeschooled for 3 years. ‘Costco’ and various book stores had grade related work books galore. I’d always expand on the subjects in some ‘real life’ way to enhance learning. Mine also enjoyed various learning programs on ‘the computer,’ there’s lots of stuff accessible online … there again, both local lib & sch dist may allow you access to some of their sites.. Make sure they learn to ‘keyboard’ correctly … returning to schools as an aid, it was atrocious watching students, even teachers ..hunt & peck ..though fast.

As for ‘group activities,’ I’d been active as a volunteer within their school and would have them attend a weekly ‘dance like’ period with their grades and friends in a gym class. Our school district encouraged us to participate as often as possible.

Whenever I read of any local ‘homeschooling groups,’ sure enough - religious based - and in science denial.. We’d explore ‘interpretive centers’ at state and federal parks, those were great - often times the only ones there, so doted on by knowledgeable staff! ...sent back A students when the time came..

I have no info on that stuff, but having them watch "Cosmos", both versions, is a great way for them to understand science.
I loved both!

You might also want to go to the site for the National Academy of Science, to see if they've got any resources, or information.
Maybe see if there are any online STEM programs, too.