I found myself needing a pause container while working in a Docker Compose stack for... reasons. A pause container runs a process that is solely used to hold onto namespace/container resources and, ideally, does nothing as efficiently as possible; this is usually done by calling the pause(2) syscall. For bonus points, it should handle SIGINT and SIGTERM by exiting normally.
(Another way of implementing this is running sleep infinity in your favorite container of choice; I initially misremembered this concept as a "sleep container". However, this doesn't handle SIGINT/SIGTERM, so you might find yourself reaching for sh -c 'trap : TERM INT; sleep infinity & wait'.)
Pause containers are a normal, everyday occurrence in Kubernetes, but the ones I could find seem to be a whole megabyte for reasons I cannot fathom, and don't make it clear what source code they were built from.
So here's mine. It's called paws, and you can pull it from ghcr.io/iliana/paws. It is pause.c from void-runit statically compiled with the musl libc. The binary is 13 KiB. It's quite possible the OCI image overhead is larger than the compressed binary.