Wondering if this group has recommendations on some of the best rewards or other savy ways to spend for traveling that are not credit card based?

Particular hotel chain, gas station, fast food based. My husband and I do a trip once annually plus to go back to our hometown typically via car and we already get decent credit card rewards for travel but wondering if there are other rewards we might be missing out on?

Next trip were definitely looking at what museum memberships might exist to do or get discounts on several locations during the trip. We do have a local zoo membership that gets us reciprocity when we travel.

Ever since I moved to a place with an airport nearby, I've been wondering about those flight deal sites -- the ones like Scott's Cheap Flights, Mighty Travels, Thrifty Traveler, Faredrop, Secret Flying, Dollar Flight Club, etc (those are just the ones I found off a Reddit thread on r/TravelHacks).
Has anyone here had any experience with these paid services?

Also, does anyone know of a way I can search for a start and end point, and find other airports nearby to fly out of for much cheaper? I remember having used such a site earlier but cannot for the life of me remember its name now :-(