How about a bunch of rice cereal, or wheat cereal (cooked)? So much smooshy fun, fine to ingest. Make or get some bread crumbs for some dry sand-like sensory play (just watch that they don't eat too much at a time, or inhale any). We do mama and baby sensory activities, like tickling with feathers, leaves, silk scarves, minky blankets, and also blowing air with straws on the baby, or spraying water with a spray bottle. In the tub or on the high chair tray with hand-whipped cream and natural food dyes if you do dairy, or some kind of baby-safe non-dairy equivalent (any ideas? We don't dairy at the moment.) Cooked spaghetti. Wool roving.
Oh, and squishy things inside a ziploc bag are also fun for babies, and not messy. As long as you are cool with them playing with a ziploc.
I also put together sensory baskets - usually with a variety of textures. So a new dish scrubby, a pine cone, a minky scrap, some wool roving, a massager, a teething ring etc. I change up this basket often.
Sensory play is obviously highly supervised. It's not usually something you can just let them do while you do something else. But it can keep their interest for a long time!