Another vote for a trangia. Need to practice using it but they are amazing!
Tea/coffee/hot choc sachets and porridge sachets - a hot drink and hot breakfast make a massive difference when been sleeping out and it's been cold/wet.
Forget the pillow - put spare clothes inside the sleeping bag drawstring bag and use that.
Definitely a warm jumper, woolly hat, spare woolly socks and gloves in case gets cold at night, so can put another layer on inside sleeping bag.
Large sandwich bags. Useful for waste, spare uneaten food, separating clean/ dirty/wet washing. In a terrible weather wild camping trip as a teenager, we resorted to sandwich bags between our hiking socks and boots. I did it to start with and friends thought I was mad and then realised I was the only one with dry feet and no blisters...
Rucksack liner. Give everything a chance of staying somewhat dry inside bag. Can also put everything inside it inside the tent if it's raining outside the tent to prevent damp seeping in. If it is wet, don't get sleeping stuff out until bedtime. If it's really, really wet or cold, it's good to have a binbag to put sleeping bag and yourself inside as once your bedding gets wet you're in for a miserable time.
Flip flops/sliders to wear in camp - lightweight to carry but it feels SO GOOD to get boots off and air feet when get into camp!
Wet wipes. They need to take all the rubbish with them but they do help quell the stench situation and freshen up a bit.
I disagree with the above re vessels - a large cup is far more useful than a bowl. You can eat pasta/noodles/porridge out of a cup, albeit over several cups. You cannot drink hot chocolate out of a bowl. You can get collapsible cups/bowls now.
Safety items - first aid kit, tweezers, whistle, compass and paper map in waterproof case - and know how to use these things - know how to take a bearing, triangulate location etc.
Thinks like elastic bands/hair bobbles are quite useful for all manner of things.
Calorie-dense snacks if hiking that do not need refrigeration.