motherboards with multiple m.2 slots
ASUS PRIME B760M-A WIFI D4-CSM Mainboard
GIGABYTE B850M AORUS PRO WIFI7 AM5 Micro-ATX Motherboard, AMD B850 Chipset, 4x DDR5 DIMM Slots, Up to 256GB Max Memory, 1x PCIe 5.0 x16, 2x M.2 Slots, Wi-Fi 7 & BT5.4 | B850M-A-PRO-WIFI7 model B850M AORUS PRO WIFI7 AMD Motherboards.
Laptop Gaming Gigabyte A16 CMHI2VN893SH (Core i7 13620H | RAM ...
2x M.2 SATA SSD slots, measuring at 80mm with 1x B & 1x M keys.
M.2 - Wikipedia
Traditional motherboards designs were limited in how many M.2 slots they could provide due to two elements: available PCIe lanes and power restrictions.