I live in Ukraine. So I donate to lots of funds like United24 and Come Back Alive Foundation. I believe it helps stop the war and the aggressor. Thousands die every day...
I will just share some links:
I bought a hoody with a Tryzub on it. Hoping to buy more stuff soon.
I also suggest NAFO (https://www.help99.co/) and Car for Ukraine (https://car4ukraine.com).
+1 to help99 (I used to live in Estonia and know the folks behind it and can confirm everything donated makes its way directly to the units)