I am trying to identify a replacement diode. It has the following written on it:
LT 5306 & 2A06
It was used between the contacts of a switch in a 12 V system. It seems like everything I find is obsolete or possibly I am not finding the right item. The picture shows the original as referenced above (smaller single unit) along with a 3 amp diodes.

 

Welcome to AAC!
Can you reverse-engineer the part of the circuit it came from? If the diode was simply for inductive spike/arc suppression across the relay contacts then you'd have a wide choice of replacements.

 

Two ampere diodes have never been very popular. From the datasheet, there is nothing out of the ordinary about the diode, so any ordinary silicon diode rated for at least two amps should be OK - it you can fit one physically. If the plastic packaged 3 A diodes are too large, you might be able to find a 3 A type in a glass package - more or less a sphere with leads. They are a bit more compact. They used to be fairly common but have fallen out of favor.

The original is rated at 800 PIV, which is very strange in a 12 V system. My guess is that something rated at 50 V would be OK, but there may be something that requires a higher voltage rating. Most ordinary diodes can easily be obtained with voltage rating up to 1000 V.