Broccoli even when chewed is really high fiber, at 3 months out I am just now handling some fiber. I use fiber powder in all my shakes.
Beef as someone else mentioned is hard to get moist enough to handle. I spent most of my soft food stage on greek yogurt mixed with protein powder and soups with very small pieces of meat. I couldn't even handle scambled eggs or more than one bite of mashed potatoes.
Your body will let you know what its ready for
good luck!