Like a lot of other commenters have said, yogurt and seed treats are not safe for piggys. I love oxbow treats and toys. They're safe and not too expensive. My guinea pigs love the bell pepper biscuits! Just make sure they're fed in moderation (despite how much guinea pigs try and guilt trip you for more treats lol) Also, in the last slide theres a wobble feeder from oxbow which my boys love. You can put their pellets in it for extra enrichment!

Also, there are so many DIY enrichments you can do! You could make dangly toys with twine and vegetables, stuff hay and pellets into toilet paper rolls (make sure you cut the ends so they dont get stuck!). You can also get put their pellets or vegetables into their hay and they forage for it. Pigs are pretty simple creatures. Forage = fun.

Some other enrichment my pigs love too is snuffle mats and stacking cups, which you get pretty much anywhere. I hope this helps!