nothing much actually. at least nothing that matches your current width and bolt pattern. unless you can find the TJ Rubicon front dana 44. but it's rare, expensive, and only kind of an improvement (is low pinion and uses a lot of dana 30 parts in the outers). of course there is a complete aftermarket axle, which is perfect except it's even way more expensive.
how to keep your dana 30 alive? upgrade the shafts an ujoints with aftermarket goodies. add a truss and upgraded steering. and don't ever jump it.
no matter what you do, it's going to need money thrown at it. big tires are not cheap, even if they are free.
a side note: my axles came from a half-ton Ford.