What are the setups/patterns useful in defence? We have typical checkmating patterns (e.g. smothered mate). Similarly are there any standard setups/patterns useful specifically for defense?

I am not looking for standard tactics like pinning/discovery/etc. I don't even know whether to call these what I look for as patterns. Just simple setups. For example

There is this interesting relationship between bishop and the pawn. They support each other.

3r4/4B3/3P4/8/8/8/5K2/7k b - - 0 1


Similarly I could think of Knights supporting each other as well.

8/8/5n2/1k1nQ3/8/8/7K/8 w - - 0 1
I'm fond¹ of this one, after sacrificing my queen for some pieces and having to deal with all my additional material being forked all over the place :

[FEN "8/3P4/P2rP3/2p2Q2/8/3n4/8/5k2 w - - 0 1"]


Note that in this setup, the knight is not bound to its square, as it can move and get back to other pawn-defending squares in no time. It's a very flexible pattern. I marked these other squares with white pawns.

It seems to be a little harder to reproduce with a bishop, without blocking too many lines, and when not being the bishop+pawn one you already mention (which nicely fits on top on it, though).

¹ Also I love knights.