I support our local Food Bank centre which supplies and distributes emergency boxes of food to people in need due to various factors such as job loss, separation, sickness, debt etc. At the moment all I can do is buy food to donate but it's something. If I didn't have the kids to care for, I'd be a proper volunteer and get stuck in because I used to survive on food parcels and I know how they can mean the difference between a meal that week or not.
I am a supporter of Catie's Kits (although there's not much I can do other than solidarity-style support because it's US based and has no donation set-up as of yet) - one of our members on another forum had a little sister who died of cancer and so the organisation was set up in her name and provides bags of fun stuff for kids to do when stuck in hospital having chemo or whatever. I've never been through that sort of thing but I have a lot of respect for the member in question and we get along so I figured why not?
I'm a qualified crisis-pregnancy counsellor (although I've not done it for some years now) and that's basically talking women (and their partners) through their options when faced with an unplanned pregnancy. It's for a pro-choice organisation which, whilst strongly Christian, does not impose personal belief when counselling people. We'll talk about it if the other person wants but no counsellor is permitted to come out with stuff that either pushes in one direction or makes the person feel bad about themselves or their decision. Counselling is actually quite difficult...I didn't think it would be that hard but when you're sitting across from someone, listening to them verbally make a crappy decision that you know will affect them badly, it's hard not to try and get them to see your point of view. You have to just listen, offer objective advice and then let them make the choice.
I'm a supporter of CLAPA which is the cleft lip and palate association - my niece was born with a cleft palate and no one knew it was there because you can't check for it on scans prior to birth.
I work for a charity aimed at blind, visually impaired and print disabled people. Charity work is actually pretty dog-eat-dog when you come up against other organisations doing similar things to you. You'd have thought you could all pool resources and work together but no - everyone for themselves, especially where funding is concerned.
Having lost two children of my own and my daughter losing her father when she was younger, we both have links with the Child Bereavement Trust and the Snowdrop Walk. My mother now works for the CBT too and when I lost the twins, the Trust were very helpful and a useful resource to have.
I also support various charities via donation boxes or whatever when I'm out and about in town - things like First Responders, Air Ambulance, kids with special needs etc. Used to buy the Big Issue every week too but the vendor doesn't sell in our town any more.
tl;dr- I support some stuff.