(Melting ice.)
Other types of necessities (in conjunction with putting frozen liquids and warm areas): child, oneg Shabbos, etc.
Understanding Some of the Rabbinical Restrictions;
Does One Have to Be Careful with Each Step to Check if They Are Stepping on an Insect?;
Eating Hard Food When It Might Make One's Gums Bleed, and Removing Meat Stuck in One's Teeth When Gums Might Bleed;