I recently took a chance on a mother board lot on Ebay.
7 motherboards, "some work some have issues". I saw some SD-RAM boards, including one with an ISA slot. Took a chance and bought the lot for $45 shipped.
Included were:
Shuttle AV18V31 s370 board.VIA Apollo Pro 133T chipset. Included a Tuleron 1400 under the heatsink and 3x PC133 CL3. Works fine so far.
Already grabbed a Tualatin P3 1400/512K off of ebay for $10 for it (so much faster), and a Radeon 32MB DDR. Currently in a vintage case was a Sound Blaster Live!.
The attachment IMG_20180915_145819.jpg is no longer available
Soyo P4x400 Dragon Lite. VIA Apollo P4X400. Included a P4 2.8/512/533 and 1x 512MB PC2100 DDR. Works, one bulging cap near AGP slot.
The attachment IMG_20180915_150151.jpg is no longer available
Asrock M266 s478 board. Supports DDR2100 as well as SDRAM. Included a Celery 1.8 and 1x 512MB + 1x 256MB DDR. Works, and that celeron is incredibly slow.
The attachment IMG_20180915_150223.jpg is no longer available
FIC PTM 865 / 848 S775 board. Intel 865G / DDR board. Included Celeron D 3.46Ghz/512/533. Untested
The attachment IMG_20180915_150233.jpg is no longer available
Asrock G41M-LE DDR2 / 775 board. Untested
The attachment IMG_20180915_150459.jpg is no longer available
ECS 945GCT-M3 DDR2 / 775 board. Untested
ECS AM2+ I-Cafe IC780M-A. Tested and has issues. Also, don't care about this board.