Is this my waste discharge pump next to my trim pump?

Doesn't look like a pump to me, looks like a sea strainer which is laying on its side. Maybe a strainer for the macerator pump

Are there any wires attached?

I thought there were wires going to it, but maybe not. I think you're right about being a strainer. Would my generator system have that? It was removed by the po.

Yes, the Gen would have a strainer

Generator water pickup strainer. It should be mounted with the access door pointed UP, and with the door about 1/4" above or below the static water line. You'll need the boat in the water to find that height, although it will be the same height as any other strainers. Your AC system will have a strainer, etc.

I just stopped by the boat and it is like you guys say. It's the missing generator's strainer. Thanks.
I'm sure the HVAC has one too. There's a second one on the port side. Slow, but sure I'm trying to familiarize myself with all the systems.