If you check the VMware HCL IO for network, you could pick one and search whatever online marketplace for that.
https://www.vmware.com/resources/compatibility/search.php?deviceCategory=io
Having said that, there are strange cases of RAM being cut off with a Broadcom 5720 installed to Dell and Lenovo desktop PCs. You can see this post and thread discussion thereafter and possibly preceding it.
https://communities.vmware.com/t5/vSphere-Upgrade-Install/Broadcom-NIC-causing-RAM-loss-in-BIOS/m-p/2932871/highlight/true#M34191
So before considering buying one you might want to check the PSREF of the ThinkCentre model you have and see what network card the model has. If it has an ESXi fling driver for an Intel NIC; you may not even have to buy one; unless you have other purpose in mind such as passthrough to VM. So the next question is where is the ESXi Fling community driver. The Flings were taken down prior to the Broadcom takeover.
https://archive.org/download/flings.vmware.com/Flings/Community%20Networking%20Driver%20for%20ESXi/
How to use the flings, probably best to start another thread if the archive gets you nowhere.