Cottage cheese as suggested by @anna_5588 is a good idea.
What’d be some good suggestions for you is highly dependant on where you want to land on the spectrum of utility and taste. Since it is fat loss you are pursuing, maybe opt for utility as it won’t be forever. That’d be something like a can of tuna and some nuts, or can of sardines, or makrell.
If taste is of greater importance to you, and you have the time, then you could make your own protein bars. Use a quality protein powder, some chopped up nuts or nut butters, and suitable flours (almond-, coconut flour). You can probably find a recipe for cottage cheese flapjacks.
For middle-of-the-road between utility/taste you might want to go for some yoghurt and a scoop of whey, maybe some berries. Greek Yoghurt is also an option.
And you could of course make your own beef jerky!