When I lived in the NT I used to have a breeding colony of 13 adults in a converted swimming pool in my backyard.
They all got a nice big feed on weekends, and I'd try to give them something different every time.
I'd go to the local farmers market and buy a bucketload of different fruits and make a huge fruitsalad with a splash of vitamins. They love any kind of soft sweet fruit, over-ripe (but not rotting) is best.
I'd roll up little balls of premium mince- the good 'heart-smart' stuff into bite-sized bits.
In cicada season we had some trees that were absolutely covered in cicadas, I'd collect a few dozen and clip the wings and tip the bucket in the lizard pit, or if I was feeling motivated I'd plough a small section of backyard for earthworms (earthworms are great- easy to share

but you must wear shoes when in a pit feeding lizards earthworms- be warned! Toes are NOT a food item!)
And I always kept a can of Whiskas Jellymeat flavoured catfood in the cupboard as an emergency food. The lizards all prefered the catfood to anything else, but its very salty and full of preservatives, so its deffinitely a 'sometimes' food
I found that different lizards had different favourites, some would pick all the grapes out of the fruit pile, others liked the strawberries, and others liked banannas best.
I never fed mine any vegetables or flowers, but that doesnt mean its not a good idea. However, avoid iceberg lettuce.
Basically they'll eat whatever you put in front of them, just be sure to provide a variety of it.