Nothing.
I used to try to make an effort but learned the hard way: when I was off sick for 2 months after a life threatening episode I never heard anything from my team (I would at least have expected a get well card)
When I came back to work from sick leave my birthday was soon after that and it was ignored (everyone usually gets a card from the team as someone keeps a birthday calendar). They instead randomly sent me a birthday card almost two month later saying that everyone was 'busy' on my birthday so they had only got around to getting a card together...which I thought was ridiculous.
I work for a charity so my salary is not great ever and I can't justify contributing to all the constant requests so now I ignore them all with no guilt whatsoever.