Yet another one that I have not filled yet, so let's do it!
- Formosan rock macaque
- Aye-aye
- Philippine flying lemur
- Sika dear
- Sumatran rhinoceros
- Hawaiian monk seal
- Hooded seal
- Galápagos fur seal
- Goodfellow's tree kangaroo
- Short-beaked echidna
- Red grouse
- Nēnē
- Kagu
- Wester rockhopper penguin
- Flightless cormorant
- Philippine eagle
- Kākāpō
- Raggiana bird of paradise
- Cuban crocodile
- Freshwater crocodile
- Tuatara
- Panther chameleon
- Sulawesi lined gliding lizard
- Frilled lizard
- Thorny devil
- Marine iguana
- Yellow-bellied sea snake
- Japanese giant salamander
- Coconut crabe
- Tasmanian giant freshwater crayfish
By the way, the Bornean pygmy elephant is also part of the list, I think you forgot to mention it.
EDIT: I realised I forgot to put a bird of paradise so I switched it with the arctic hare who also lives on mainland.
This list contain surprisingly few mammals.