Mining and jewelry.

Mining and engineering.

These three combinations are all very powerful.

Forging has holes, which may be equipped with gems. You can make your own equipment and weapons. This is of course great for paladin plate armor.

There are exclusive gems in the jewelry, which are much more powerful than ordinary gems, so they must be powerful.

Engineering, this is even more awesome, rocket boots, it must be awesome for the short-legged guy of the paladin. And many engineering-specific ones are super awesome.