It'll be much simpler topic than previous, but with more warnings ahead:

Our adapters choice - used Dell Broadcom 57810S Dual Port 10GBASE-T Converged Network Adapter

For $45 only per adapter (cost of one good new single port Intel 1Gbit separate card)

https://www.ebay.com/itm/Dell-Broadcom-57810S-Dual-Port-10GBASE-T-Converged-Network-Adapter-HN10N-Low-P/132761054157

Few main reasons:

• Cheap
• Ability to attach adapter to different networks or join forces of two ports to reach 20Gbit (but usually it'll be only for multiple transfers).
• Official support for RDMA, rare for adapters outside Mellanox. Note that actual support for it in Windows drivers must be checked. I saw negative reports on this.

Stay away from relatively cheap (<$110) new copper based 10GBASE-T adapters, usually using Aquantia AQtion controller. They are fine things, but made for consumer market and do not have server grade drivers with necessary features and not designed for low CPU utilization.

On cables

If length of the cables is small you can use worse cables than recommended, here I mean old Cat 5e patches and cables, in case they are good quality and not damaged. Plus EMI in your place is not extreme. Cat 6 cables just have more turns in each twisted pair per same length, plus use thicker wires. Chinese Cat 7 patch cords are also pretty nice shielded things, if not too long (as they sometimes can save on copper :-) )

Otherwise follow official recommendations and in case of significant EMI use shielded cables.