Electronic – What kind of 3×2 connector is this

There's generally only two important variables in spade connectors:

1. Blade (not socket) width (the thickness may vary as well, but it should be prescribed by whatever the width is),
2. and if it's on a wire (versus a board), wire gauge it accepts.

Measure the blade width (I've only ever seen them specified in inch sizes, 0.187, 0.250...), and see if there's a good match on some parts catalogs (here's the Digi-Key category). After that, pick the one that fits a wire gauge that will safely carry your current.

Three possibles in order

1. Ferrite Inductors, used sometimes to reduce conducted noise on power supplies. DC Resistance is zero, but 10-1000 ohms at high frequency.
2. 'Poly Fuses' 'PTC Resistors' 'Resetable Fuse' Often have low resistance. When they heat up the resistance goes up which limits the current due to a fault.
3. Sense Resistors, used to sense current. Often these have very low resistance (much less than an ohm)
4. Zero Ohm resistors, sometimes these end up on power supply rails so that engineers can measure current.