socket 7 motherboard in ATX form factor
http://www.philscomputerlab.com/gigabyte-586atx.htmlheres a list of more socket 7 motherboards that use the ATX formfactor:
http://www.interloper.com/resultsmb.php?slot%5B%5D=Socket+7&model=&chipset=&bios=any&pcislot=&isaslot=&db9=&htx=&1X=&2X=&4X=&8X=&16X=&formfactor%5B%5D=ATX&width=&depth=&sataport=&usbport=&audios=any&btnSearchMb=List+Formwhich includes:
Abit/AB-AX5, Asus/TX97-X, Asus/P5A, Gigabyte/GA-586TX2,
https://www.philscomputerlab.com/gigabyte-586atx.html https://www.gigabyte.com/Motherboard/GA-586ATXCPU
Intel Pentium®Processor 75-233MHz
AMD®5K86, K6®(P166 to P233) Processor Support
Cyrix®/IBM®6x86/686L P100+ to P166+ Processor Support
ZIF Socket 7 for Intel Pentium®OverDrive® Processor
(Auto Detect & Setup Intel Pentium®MMX®Processor,Cyrix®/IBM®6x86,6x86L, AMD® K5)
Chipset
Intel 82430 TX PCIset
UMC 8661 I/O chip (1Mb/Sec)
Memory
4 x 72-pins SIMM and 2 168-pins DIMM (3.3V SDRAM) sockets support 8MB to 256MB DRAM Size
Use combination 0f 8/16/32 MB 3.3V SDRAM and/or 4/8/16/32/64/MB SIMM module DRAM with Fast Page Mode or EDO DRAM.(see table in the manual for the mix combinations).
Expansion Slots
3x PCI 32-bit slots
3x ISA 16-bit slots
1 PCI/ISA Share slot
Internal I/O Connectors
AT Keyboard & PS/2 Mouse support
1x Floppy port (360KB-2.88MB)
2 x Serial ports (16550 high-speed)
1 x Parallel port (EPP/ECP)
1x USB port (USB cable optional with additional fee)
BIOS
128KB FLASH EEPROM
Award PCI BIOS with green, plug and play features support
Other Features
ACOPS, ACPI, SIMM and DIMM mixable, Switching regulator(10A MAX).