Gramine
A library OS for Linux multi-process applications
...It was formerly known as Graphene, but the project renamed to Gramine to avoid naming conflicts and to reflect its broader ambition beyond the original research prototype. The idea is that instead of running a full guest OS in a VM, you embed your application inside Gramine, which handles the system-call interface, process and thread management, file system, and network abstractions — everything the application expects — but strips out the overhead and complexity of a full OS stack. One particularly strong use-case is confidential computing: Gramine supports Intel® SGX enclaves, allowing applications to run inside hardware-protected memory regions even while using standard Linux binaries with minimal porting effort.