This is where socketed CPUs started. The venerable 486’s of all varieties called Socket 1 home.
Intel i486 SX 25Mhz SX679
Lower cost CPU with no FPU, clocked at 25Mhz rather than the 33Mhz of the DX (with FPU) counterpart.
Intel i486 DX2 66Mhz SX762
Late 486 CPU with FPU, internal clock running at a multiplier of 2 for a clock rate of 66Mhz with outside bus running at 33Mhz.
Intel OverDrive DX2 50Mhz SZ934
Intel Overdrive CPUs were often sold as “plug in” upgrades for older systems, and were very similar in terms of performance. They were sold with permanently attached heatsink. This one appears to be a clock doubled version, running at 50Mhz, so ideal for upgrading boards running the original 486SX-25.
Intel OverDrive DX2 66Mhz SZ904
Another upgrade CPU, this one probably better suited to upgrading boards originally running with 486DX-33s.