what compounds, combined in an exothermic reaction, produce aluminium as a by-product?"?

Question

it may not actually be possible but I'm curious

Answer 1

You need to take a look at the reactivity series at:

http://www.gcsescience.com/r1.htm

Take an aluminum oxide or salt and mix it with an element that is higher on the reactivity series.

See http://www.gcsescience.com/r5.htm for proof of my answer.

Answer 2

Possibly the decomposition of an organometallic compound of Al. Maybe the decomposition of AlH3.