So as a general rule most older hardware should be supported OOTB. Although by default, only open source drivers are included. You may have issues with ethernet drivers that don't have open source drivers available, or new chips developed and produced within the last few years.

You can work around the former by enabling the non-free repo and installing the relevant firmware package(s), have a read on the Debian wiki for pointers. Unfortunately, working around the latter can be a real pain. If you hit that issue, then the only real workaround that I'm aware of is using a newer kernel (and the relevant driver code). If it's packaged in Debian testing then it shouldn't be too hard to work around. But if it's not already packaged for Debian then it can be a real pain (as it is with any OS that doesn't have specific drivers packaged).

IMO, rather than trying to accommodate all hardware, personally a better way to go would be to audit the hardware that you may be using and then just add the necessary drivers.

WRT to using TKLBAM, you could indeed use that, but it would still require you to install the TKL OS (e.g. from the ISO). And if the image doesn't support your hardware OOTB, then getting it working from that won't be any easier than getting a clonezilla image to work.

IMO though, unless you have really crap hardware, or crazy high load on your servers, running on bare metal is a major waste of resources. IMO you'd be better off using some sort of hypervisor with your workloads running as VMs (or containers depending on how much isolation they need). Containers in particular are an awesome way of maximising hardware utilization as they run close to bare metal (less than 5% overhead) but allow "over allocation" of resources if you want.

My personal preference is ProxmoxVE. I have a small server running and I have about 10-15 VMs/containers running (a Windows VM, plus a couple of TKLDev instances, plus a heap of TurnKey appliance containers. Mostly I just use them for testing but I have a couple running full time (e.g. my home file and media server). I also have Proxmox in production at my old work (I still do a bit of IT support). That has 2 Win 2k8r2 servers and some TurnKey containers and it all runs on desktop hardware. TBH Windows server runs much better hypervised than it ever did on real hardware. And if you have a couple of server and a good storage setup you can configure clustering. You can then even migrate live VMs from one node to another.