A drop in the ocean
— if an amount is a drop in the ocean, it’s a very small portion of the amount that’s needed; a ray of sunshine
— something is a ray of sunshine if it brings happiness to someone;
a voice (crying) in the wilderness
— you’re a voice in the wilderness, or a voice crying in the wilderness, if you’re expressing an unpopular opinion or insight; beat around the bush | beat about the bush
— if you beat around the bush, or beat about the bush, you don’t say something directly, usually because you don’t want to upset the person you’re talking to; down to earth
— if someone is down to earth, they are practical and sensible.