I second Alpine. I've never had issues with it, and while it can seem a little strange vs. the bigger distros, it functions well and is kept up to date.

I honestly just use Debian server or the lightweight Ubuntu server because it’s what I know.

I have a fedora server for fun and it’s a bit more of a hog but I have the resources to spare.

Vanilla Debian for me as well. It's the right balance of light, I know how it works, and everything I need is easy to get.

I go straight for a Debian net install and when it comes to tasksel, just SSH and system utilities. I've got a single image that I need to update, that is ready to be cloned, have Ansible thrown on it, to bring up whatever I need.

Unfortunately I'm doing my lab in virtualbox on my laptop since my desktop is in storage and my server needs new hard drives... And can't host Proxmox because ancient celeron CPU. Need an additional server for Proxmox.

What about Ubuntu server minimal installation?

I use the cloud images of Ubuntu server, but many other distros also have minimal or cloud/cloud init images. They're small and with minimal packages installed. Plus you can also use cloud init to make deploying new servers almost painless via templates (even better than the standard templates in proxmox). Btw if you have a bunch of VMs with the same OS your system will automatically use KSM to reduce memory usage.

+1 for Alpine. There's also Proton, but who knows it's future since the VMWare buyout.