i think this is a very good question! it's hard not to feel cheerful when helping other people to feel cheerful, so here are some ideas toward that end... https://twitter.com/RebeccaforWA/status/1334155764819062785
lots of domestic violence shelters have moved to asking for holiday gift donations through amazon wishlists this year. you could set a budget and go 'shopping' for these families with your family: https://www.safehaventc.org/santassack/
similarly, you could organize a closet clean-out and pass along some warm clothes in good condition to nearby shelters, or even send some work clothes (because who goes into the office anymore!) to centers that help people dress for job interviews: https://www.stanns.org/donate/wishlist
remember RIP Medical Debt? you could get your church, temple, synagogue or faith community to organize a fundraiser to relieve millions of dollars in medical debt! seems like a cool holiday gift: https://ripmedicaldebt.org/donate/
also: lots of local nursing homes and elder care facilities are now sponsoring pen pal or phone pal programs, since visits are so risky right now. i find that my four-year-old LOVES being phone pals with basically anyone: https://www.nytimes.com/2020/04/10/us/coronavirus-seniors-pen-pals.html ; https://app.monami.io/phone-bank/welcome
lastly, if you're a photographer or digital retouch artist, you can volunteer to photograph (or edit photos of) families with their stillborn children -- or donate to this beautiful nonprofit that provides this very special service to grieving parents: https://www.nowilaymedowntosleep.org/volunteer/
i also recommend baking your way through King Arthur's holiday classics baking list, listening to a ton of Christmas music, driving around and looking at lights, and doing your part to stay healthy/be safe: https://www.kingarthurbaking.com/recipes/collections/holiday-classics
i'm also sending lots of cookies and other baked stuff by mail, since food is a low-risk transmission vector, and everybody likes treats at the holidays. if you like to bake even a little, try it! people love getting boxes in the mail. https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/can-coronavirus-spread-food-water/faq-20485479