This is a Home Assisatant Lovelace card that seemlessly combines any other cards into a single card.

It was heavily inspired by stack-in-card, but takes a completely different approach to combining the cards. On top of that, it has a visual editor, allowing you to fully create your combined card from the UI. You can nest cards inside a combined card as deep as you'd like (i.e. use vertical and horizontal stacks as you see fit) without performance issues and without re-introducing borders and shadows inside the nested stacks.

Here is a stack of cards created using mushroom cards.

This stack looks pretty nice on its own, but can become chaotic inside a dashboard with even more cards.

With Combined Card, that entire stack can be placed inside a single card, giving it a better group look.

If this is too undefined for you, you can combine the cards more granularly, in this example into a porch card and a backyard card.