Work With What You've Got

The terrain itself becomes a weapon when you look hard enough.

When you cleverly use your environment to harm or impede your foe(s), roll +INT. On a 10+, pick 2; on a 7-9, pick 1.

Interrupt or thwart their action(s)
Create an opportunity that grants you or an ally advantage on the next roll to exploit it
Deal damage appropriate to the source: d4 for bruises or scrapes, d6 for bloodshed, d8 if it would break bones, d10 if it would kill a common person