I personally believe that the most impact-per-dollar you can get is by donating to local volunteers with small fundraisers.
Understandably, donating to a random person without concrete proof that the money goes to the right place is a bit risky. That's why Vyshybanky exists. It's a platform that aggregates and promotes small fundraisers, all while verifying volunteers and requiring reports.
Vyshybanky is a great project, and I can personally recommend it.
If you want to go for a more traditional way, here's a list of trusted charity organizations that I recommend:
And remember - no donation is "too small".