Latvian Gambit recommendations The Latvian gambit:

e4 e5 2. Nf3 f5!?

leads to a sort of King's gambit reversed. I've had a large winning percentage for this opening as Black in club games. Would this opening be good for a 1500-Fide level tournament?
It might barely be playable at 1500 FIDE. However, as others pointed out, if someone prepares for you, then you will be in big trouble.
My recommendation to to avoid playing this gambit at all costs.
I'm around ~2170 USCF, and my main repertoire is non traditional(morra gambit, kings gambit, alekhine, dutch....). This is coming from someone who's played many gambits over the years.
I tried earnestly to incorporate the Latvian gambit as some sort of surprise weapon. It is just unplayable. Even when my opponents were significantly weaker than me and obviously didn't know what was going on in the opening, they usually get an edge, and it could be a big one too. If they happen to have studied the latvian, then you are pretty toast. I don't even recommend it for blitz.
This is just my anecdote, but it's clear to me that for strong chess players the latvian is not sound, and it is not hard for white to deal with.