This would be part of a low-end office machine, an "e-machine" styled system, a low cost home/family system. Maybe something from a Compaq. The riser card goes in the big slot, and it would play host to a soundcard and modem if those options were selected.
It's curious the socket cpu looks like a 486sx-25. That's a low-end 486, and those were usually soldered on at the factory. The socket would remain empty and provide the user a path to something like a DX2-50 or 66. There are jumpers to support such an upgrade. So perhaps the board was made toward the end of the 486's reign. When all the SX-25 chips were coming back in and a surplus built up.
There is also a socket for more video ram too. It comes with 512K now, but you can add another 512K for a total of 1MB. CL5429 was pretty much standard VGA chip back then, and it itself could support up to 2MB for higher resolutions - again supporting the idea it's a low-end consumer configuration. It's also 100% IBM VGA compatible and BIOS compatible. There is also what looks like the standard VESA feature connector for external mpeg decoders which were popular back then. And the chip is Vesa Local Bus.
The board also has all the standard interfaces of the time, 2x serial, 1x parallel, IDE and floppy controllers, clock, VIA chipset, standard memory. It's rather integrated with all this stuff on-board. While that could be an annoyance back then, it's a benefit today. It's all there!
Here's discussion about the COAST module, the socket by the 486.