From my current experience and partially beyond the technical realm (though probably out of scope for your question):
Adapters / multiple socket outlets for your devices
Maybe a second (portable USB-) screen
2nd phone/sim slot for any MFA/SMS sent to your current number, since you will probably have a local sim card in your current phone then
Read up on culture shock theory. There will probably be an emotional low point a few weeks into the experience. Then you know what it is and that it will likely pass.
Remember that you are working abroad and that your free time is limited. There is a challenge to set up new routines for your daily life (like where to shop, what to cook, ...). It takes a while to really arrive in a new place.
Have something to do after work and after sightseeing. I am happy about my exercise routine. But I also recommend having a hobby for socializing.
From my current experience and partially beyond the technical realm (though probably out of scope for your question):