There are some fully option- featured top tier gaming/overclocking mini ITX motherboards (especially ASrock and ASUS brands) for mini towers and Small Form Factors PCs, especially that the tendency nowadays is to go for one powerful Graphic Card (instead of juggling with SLI and Crossfire with their drivers, scalability and heat issues) so one PCIe 3.0x16 of the mini ITX board would largely suffice, some of them even feature dual M.2 NVMe !
Only difference is number of PCIe expansion ports, number of fan headers, and eventually number of Sata ports.
A good compromise would be getting a Micro ATX motherboard which size is in the middle between ATX and mini ATX and has advantage (depending on the brand and model) over mini ITX is few extra sata ports and PCI expansion ports and an extra PCIe 3.0 for a SLI or Crossfire
Basically a top tier brand name mini ITX would pack more features and would bring more overclocking potential than an entry or mid level full ATX motherboard.