Please consider using handkerchiefs instead of tissues – they last a lot longer and are much better for the environment.
Toilet paper – carry some for emergencies but please, please bury everything. Anything else is unsightly and thoughtless and tissues/toilet paper seem to take ages to degrade.
First Aid – if you are doing a self-guided trip you will need to carry your own complete first aid kit. If you are doing a guided trip then you should still carry personal medications and a blister kit.
Some people like to carry a fly net during the hot summer months.