If staying in range of a developed country's rescue resources......
After the first 2 PLBs/EPIRBS....maybe a third....everything else is gravy.
But consider a handheld VHF and some water....plus a couple waterproof flashlights.
Proper attire for cold water ...if there... such as float coats and or survival suits without question should be alongside.
Plus your ID packet with credit cards and wallet...phone if you aren't sure you backed up all your contacts...
If traveling far from land and rescue resources...there are some great lists on the net and are too long to retype for me at least.