when I run OpenWrt on X86 and want 10G NIC, where can I find a list of supported NICs?
Since 10G is most fun with fiber connection what SFP+ support can I expect?
It's probably harder to find a NIC that's not supported.... OpenWrt is Linux and you can't sell a NIC that's not supported by Linux anymore. Worst case is that you have to add the OpenWrt packacging for a new driver. But that's also unlikely.
You could take a look at the drivers in https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=package/kernel/linux/modules/netdevices.mk to verify OpenWrt support.
That's more difficult...
Most of the NIC drivers have integrated SFP support, so the answer depends on the driver. Some of them offload SFP functions to firmware and can therefore block "unauthorized" optics even if the driver itself is open source.
Personally I like the older Intel X520 adapters becasue they don't have such SFP problems. The driver even comes with a knob to disable the warnings:
bjorn@miraculix:~$ modinfo -F parm ixgbe max_vfs:Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63. (Deprecated) (uint) allow_unsupported_sfp:Allow unsupported and untested SFP+ modules on 82599-based adapters (uint) debug:Debug level (0=none,...,16=all) (int)
But these NICs are a bit dated now. If you're going for some more modern then you might have to buy vendor specific optics. At least for SFP+ optics. I believe many driver/NICs will accept any SFP (i.e 1gig) or DAC and just be difficult wrt non-DAC SFP+
stick to intel cards, x520 can operate on 10 or 1gig sfp module, chelsio don't have drivers , mellanox same and broadcom are lottery for performance. an netgear wc7600 v1 will work nice but litlle noisy - it's server grade appliance