650b <33m tyre recommendations?

Recently bought a new bike and due to smaller frame size it has come with 650b/27.5 wheels with 40mm tyres. Looking for something thinner for the cross season, 33mm or less but really struggling to find anything – any recommendations?

Not keen on purchasing a 700c wheelset just to get more tyre options and the set that comes standard are pretty good (other than the size!)

Thanks