Comment 15 for bug 1737428

https://www.freedesktop.org/software/systemd/man/systemd.network.html#VRF=

VRF= The name of the VRF to add the link to. See systemd.netdev(5).

vrf A Virtual Routing and Forwarding (VRF) interface to create separate routing and forwarding domains.

[VRF] Section Options
The [VRF] section only applies for netdevs of kind "vrf" and accepts the following key:

Table=
The numeric routing table identifier. This setting is compulsory.

Example 15. /etc/systemd/network/25-vrf.netdev

Create a VRF interface with table 42.

[NetDev]
Name=vrf-test
Kind=vrf

[VRF]
Table=42

So there is backend support in networkd to create tables / vrf, and add link to a given vrf. Not sure about if routes are hooked up in networkd too.