Good scent toy/puzzle for older dog?

Kong Wobbler is a good kibble dispensing toy.

It can fit a cup and a half or so of dry food which means its actually usable to feed a meal for a larger dog, very strong plastic holds up to being knocked around, its simple to learn to use but not so simple that the food just falls right out.

Its got a weighted base like those kids toys from back when The Weebles or those blow up punching bags for example.

The puzzle toys with sliding compartments like posted above seem better for smaller dogs or very patient types. Big dogs seem more likely to just pick it up and shake or smash the thing. If you get one on a good sale, worth a try but I'd start with some simpler larger toys first.

You can hide treats just using household objects like plastic cups around the living room for the dog to sniff out.

I do home made as well. I'd so buy that kong wobbler if only I fed kibble though. All the store bought kibble toys I've had were noisy, slid under furniture, hard to clean and fill, hated them with a passion. Unfortunately the dogs adored them so I suffered.

A dry clean water or milk jug with a dinner's worth of kibble is so much fun to bop around. My first dog didn't quite get it and would chew the opening so nothing could come out but she still loved it even if she had to ask for help sometimes. Second dog would hunker down in his bed, pop off the screw top and empty it out in his bed somehow. Usually boxes belong to dogs. I'll open a box of crackers, one dog gets the box with some cracker crumbs inside and the other gets the bag with a few crumbs with top wound tight and reversed on itself. Riffing on the snuffle mat/IQ towel test I just now folded a towel over and around a crumbled cracker. Happy dogs for 10 minutes. All are supervised as dogs will try to eat things that smell like food and none of these are safe chews.

A real snuffle mat? I've long scattered handfuls of tiny bits of food on the floor or patio but why not in the grass? We call it chicken scratch and my current dogs work long and hard for vegetable bits as well as bready or meaty bits.

How about real nosework? Lots of info online and to start out is easy. Pair a scent with food, then the treat is offered after dog finds the scent and then work to making the scent harder to find. They aren't looking for food but are using noses. Could be a great bonding exercise as you are working together to find that lost bit of vanilla or whatever.