I use Soreen banana loaf. If you get the “lunch box bars” you get handy 150cal bars wihch fit 3 or 4 to a pocket.
My last 100k included Soreen 3 bars, I eat 1 every hour on the hour, and an energy+caffiene gel 1 hour from the end.
Haven’t seen much mention of it but “Nectar” juice from the makers of Goodness shakes seems to be a superb addition to my bottles. You can mix it in 3 strenghts, I had 1 bottle at middle strength (exercise strength for hydration) and 1 at hydration + red bull strength – this one I use last – for 100 miles distance, 1 bottles normal strenght for short rides or 2 for 100k’s.