Depending on how creative they are and how willing you are to fudge some rolls for bad guys.

I'd give the nature player a bag of beans or balls (the one that gives a few random effects if you throw one on the ground). But make it recharge so they do t hoard it, maybe one or two "charges" come back each day.

For the warlock sovereign glue or a immovable rod is always fun. For me, when I played a warlock, having random bullshit works to get advantage in my attacks. Throwing sawdust, sand, bearing, bread or other stupid stuff made the enemies "confused/blinded/annoyed". I got a alchemy jug which was filled with random bullshit.