I'll do the zinnias in two posts to get around the limit on number of photos per post. I started out several years back with a standard mix of seeds, I can't remember where I got them. But I've been saving seeds for several years and like the colors I'm getting.
I don't know that I have a favorite zinnia. Whenever I see an orange that just blows me away I see a brilliant yellow or red that is just gorgeous. Some of those purplish ones are fantastic.
I got a packet of zinnia seeds from somewhere, probably Lowe's, 7 or 8 years ago and got a couple of whites, a couple of oranges, with the rest a variety of darker pink/purple shades. I saved seeds of the whites, orange, and purplish and started getting some of the other colors. It's just been the last two or three years that those brilliant yellow and reds started showing up. I save seeds from the various colors and keep them separate so I'm sure of planting some of each.
I got a packet of marigold seeds from somewhere online to make sure I got the "French" marigolds that were supposed to have all those miraculous properties for companion planting. The original colors were solid yellow, solid orange, and a patterned red they called "sparkle". Again I saved seeds from the separate colors. The first few years I just got the colors and patterns of the original flowers but the last three or four years some of those other patterns started showing up. That original red sparkle pattern seems to have gone away but that's OK. I like those other patterns I'm getting much better.
There are a lot of really pretty flowers out there. But for adding brilliant bright colors all summer long I don't think you can beat marigolds and zinnias. And they are so easy.