I tend to donate lots to charity shops - in advance enough of Christmas so that they should be able to put them out for sale (early November). I often also buy things there.
I buy a trolley load for the local Lion's Club appeal - I put together "a family shop" with lots of ordinary food and cleaning items etc, things like toothbrushes and toiletries, nappies and baby wipes etc, and a few nice treat things for the festive season too. (I've often been asked if I was sure as I drop it to the collectors - they usually only get a couple of items each from the shoppers who do give to them whereas I come over with a groaning trolley - but I have been gathering things for weeks on special offers and bogofs etc so it doesn't actually cost as much as it seems).
DD also buys and wraps a toy for the Lion's Club toy appeal - picking something that she knows someone her age, or younger, would enjoy.
At work, there is someone who arranges a collection for the homeless charity in the city centre - looking for warm hats, socks, gloves, toiletries and bigger things if we want. So I usually put a few bits into those sacks in the hall.
Something I tend to do all winter is give a couple of the homeless guys that are regulars near work (and actually homeless as opposed to just beggars) my coffee cards. The ones where the coffee shop stamps for each hot drink you buy and you get a free drink when it's full - it means they can get one when it suits them. As I don't like to give money. But there are a couple of coffeeshops that are happy for me to "buy" a few coffees but stamp up a bunch of cards instead and I can hand them out - I tend to do that to have extra when the weather gets particularly chilly.
I buy cards to support a few different charities, and while I buy them in stores if I don't have time, I will get them direct from the charity if possible to maximize their income from them. And we have done a few different Oxfam charity presents for family over the years - there are a few goats, chickens, sets of classroom books and a couple of limbs for amputees floating around.
While I didn't want to do the Samaritan's purse boxes, I did research it before and found a few other places that did similar collections without the same philosophy behind them. The Humanist society did one, and "Mary's Backpacks" was another that I can recall. I don't really have a chance in recent years to put those together though.
There are various charity collections and draws that I contribute to (they explode at Christmas but there are plenty throughout the year), or things like "Jersey Day" in October at work.
I volunteer for an organization supporting children year round - the Scouts. That might not be the most worthy, but while we are in an affluent area, there are also parts with serious deprivation and the troupe actually has a number of families from the less well off parts as well. We are supporting all of them to develop into good and responsible and able young people and adults while giving them opportunities for fun and adventure.
I don't tend to advertise most of those - they are just part of who I am and what I do. I will tend to buy locally and ethically where possible. I give my old books to old folks homes and charity shops. I give to various collections but don't sign up on the street to monthly subscriptions. But I just do what I think I can to help others around me - and I know that is terribly middle-class of me, but I do work FT, I do have a DD to support at home and I do also like to enjoy a certain quality of life as achieving that is quite stressful (I am the person with a permanent pensionable job in our house so I need to stay in it - but I also need to be the person supporting DH in his travels, keeping the household running and supporting wider family from afar). So I'm afraid that it does need to fit around what I find possible.