I always used to take Rich Tea fingers with me everywhere when DS1 was small. He'd usually have 1 of those and a banana and some grapes. Much much cheaper than baby biscuits and I think from memory have less sugar etc than those Biscotti ones.
With everything, check the salt and sugar content on the packet. You'd be amazed how much this varies e.g. between different types of bread.
We gave plain grown up rice cakes right from the start. The plain Kallo organic ones are excellent for low salt etc.
Also try these: plain breadsticks / grisini plain tortilla wraps, poss with some soft cheese spread finger sandwiches - our faves are soft cheese and grated carrot toasted bagel cut into wedges or just toast!
Sorry the list is so bread-heavy. It does get better once they can eat a little packet of raisins or whatever.
Bread sticks you can get mini ones too, Crisp breads, cherrios, crackers, lots of fruit, pitta bread, bagels, chipatti, Veg sticks like carrot, pepper. Some spreadable cheese always goes well with most things Cucumber
Have never used 'baby branded' foods. Just normal ricecakes/breadsticks etc (low salt varieties are fairly easy to find). I tend to take fruit out as a snack or a little tupperware with roasted veg sticks and cheese etc. TBH I give pretty much the same out and about as I do at home or just bf if we arent somewhere I can easily give him solids. DS 8 1/2mo and BLW.
I'm struggling a bit with snacks that aren't sweet/fruit or cheese! DS has toast for his morning snack at nursery so I don't want to give him more bread in the afternoon. We eat dinner together later so he needs a substantial snack/light tea at around 4pm and I seem to be stuck in a rut of banana, raisins and cheese sticks.