Chia Seeds and/or bay leaves

Chia seeds yes - I have them with breakfast each morning. Bay leaves no - I think they're an acquired taste and can't imagine eating them every day. Haven't noticed any huge change in my BG since eating chia seeds. Biggest difference to mine (especially the fasting level) has come from a fairly strict intermittent fasting/restricted 8 hour feeding window.

I've always used fresh bay leaves in cooking (when suitable) but can't say that since I've been diabetic I've ever noticed any change in glucose levels.that could possibly be due to using them.
I also have some chia seeds in one of my low carb loaves, but like @Indy51, a strict low carb diet is the main control and management for my glucose levels, and I don't actually believe that any one particular supplement is going to work as well as this diet. They may or may not be the icing on the cake... but there's only one way for you to find out if they work at all for you.

Robbity

Agree with @Robbity - I don't believe in magic bullet 'super foods'. The main factor in blood glucose control is restriction of carbohydrates. Judging by various posts I've read here over the years, the supplements that seem to have the most promise are alpha lipoic acid, bitter melon and possibly a few others. But again, they won't work by themselves without the dietary changes.