What I got from your post.
1. Parking lamps work correctly
2. The CHMSL ( Center High Mount Stop Lamp ) works correctly.
2.1. The stop/turn/tail lamps on the bed of the truck, only the parking lamps work, nothing else ( no brake, no turn ).
3. No turn signals all the way around the truck.
Not too sure where you were going by checking every smaller fuse in the cab and under the hood., nor what the method you used to check them is.
When testing fuses, they are tested installed with a meter set to VDC and check both pins on the back of the fuse.
1. Do your hazards work ?
1.1. Check front and rear for this.
2. Check CJB (aka Central Junction Box / Cab fuse panel) fuse #23.
2.1. This fuse is only hot in run position.
3. Check BJB ( aka Battery Junction Box / Engine compartment fuse panel ) 19 & 20
3.1. These are only hot when the brakes are on, or will pulse DC when the turn signal is on.