Bootstrap 4 is now fully released and out of beta, so looking forward to great things.
Check out some of the new features shown in these new BS4 templates:
The Blog layout - https://getbootstrap.com/docs/4.0/examples/blog/
And the Checkout demo - https://getbootstrap.com/docs/4.0/examples/checkout/
And this Fruity one - http://getbootstrap.com/docs/4.0/examples/product/
