What would cause the 30amp ignition fuse on 95 ford ranger to blow?

Look for rodent damage. Try to isolate cause by unpluging connections to modules.

Disconnect battery and measure fuse load side to battery neg (ground) with DMM. Likely it is zero ohms (dead short).

That is the torque converter clutch lockup relay that is bad,

Ignition switch needs replacing. How To Install Replace Ignition Switch Ford Ranger 95 04 1AAuto com

If fuel pump is seized, you should be able to disconnect the hot wire from the pump, turn on the key and fuse stays in tact. My bet is on seized pump pulling too much current causing the fuse to blow.

There is a starter relay in the circuit in addition to the starter solenoid.
If you have replaced the components, I would guess the problem is in the harness or a connector.

This means you have a dead short, you will need to look around engine area for bad wiring or component, you will need to start disconnecting components under the hood in the engine like injectors o2 sensors alternator , my first test would be to disconnect the small wire to the starter and leave the big one one for now and see if the fuse dtill blows, i have found this to happen when the starter is shorting out inside, if you turn the key and the fuse doesnt blow then replace the starter, remember the small wire on the starter. good day.

Check the wiring where it connects to the socket for the bulbs in the brake lens and front turn singals

you have a short to ground in the wiring ! Introducing the ECT2000 Short and Open Finder

you might have blowed blulbs check that also there might be what is called a fuse link in the wiring

Hello
Disconnect the fuel pump
then see if you still blow the 30 amp fuse many times when the fuel pump goes bad this will blow the 30 amp pdc fuse
RD