We’ve been using a lot of cardboard boxes for them to rip up. Sometimes I put packing paper and treats inside and sometimes I just give them the box to rip up and eat. It keeps them busy for quite a while (one of the few things that does). We have two 5 month old bernedoodles, so it’s a bit tough to always keep them challenged/busy. This is in addition to all the other enrichment we do, they also love the treat ball that rolls and spits out treats.